diff --git a/substrate/Cargo.lock b/substrate/Cargo.lock
index a40f588d29..5d32c8882b 100644
--- a/substrate/Cargo.lock
+++ b/substrate/Cargo.lock
@@ -3999,6 +3999,7 @@ dependencies = [
  "libp2p 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 3.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
  "sr-version 2.0.0",
diff --git a/substrate/core/consensus/common/Cargo.toml b/substrate/core/consensus/common/Cargo.toml
index 5e55d555dd..a64ae120f4 100644
--- a/substrate/core/consensus/common/Cargo.toml
+++ b/substrate/core/consensus/common/Cargo.toml
@@ -18,6 +18,7 @@ runtime_version = { package = "sr-version", path = "../../sr-version" }
 runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
 tokio-timer = "0.2"
 parity-codec = { version = "3.3", features = ["derive"] }
+parking_lot = "0.7.1"
 
 [dev-dependencies]
 test_client = { package = "substrate-test-client", path = "../../test-client" }
diff --git a/substrate/core/consensus/common/src/import_queue.rs b/substrate/core/consensus/common/src/import_queue.rs
index 4d64d799b1..26ae181b51 100644
--- a/substrate/core/consensus/common/src/import_queue.rs
+++ b/substrate/core/consensus/common/src/import_queue.rs
@@ -31,6 +31,7 @@ use crate::block_import::{
 };
 use crossbeam_channel::{self as channel, Receiver, Sender};
 use parity_codec::Encode;
+use parking_lot::Mutex;
 
 use std::sync::Arc;
 use std::thread;
@@ -97,7 +98,7 @@ pub trait Verifier<B: BlockT>: Send + Sync {
 }
 
 /// Blocks import queue API.
-pub trait ImportQueue<B: BlockT>: Send + Sync + ImportQueueClone<B> {
+pub trait ImportQueue<B: BlockT>: Send + Sync {
 	/// Start background work for the queue as necessary.
 	///
 	/// This is called automatically by the network service when synchronization
@@ -105,8 +106,6 @@ pub trait ImportQueue<B: BlockT>: Send + Sync + ImportQueueClone<B> {
 	fn start(&self, _link: Box<Link<B>>) -> Result<(), std::io::Error> {
 		Ok(())
 	}
-	/// Clears the import queue and stops importing.
-	fn stop(&self);
 	/// Import bunch of blocks.
 	fn import_blocks(&self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>);
 	/// Import a block justification.
@@ -115,13 +114,96 @@ pub trait ImportQueue<B: BlockT>: Send + Sync + ImportQueueClone<B> {
 	fn import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>);
 }
 
-pub trait ImportQueueClone<B: BlockT> {
-	fn clone_box(&self) -> Box<ImportQueue<B>>;
+/// Basic block import queue that performs import in the caller thread.
+pub struct BasicSyncQueue<B: BlockT, V: Verifier<B>> {
+	data: Arc<BasicSyncQueueData<B, V>>,
 }
 
-impl<B: BlockT> Clone for Box<ImportQueue<B>> {
-	fn clone(&self) -> Box<ImportQueue<B>> {
-		self.clone_box()
+struct BasicSyncQueueData<B: BlockT, V: Verifier<B>> {
+	link: Mutex<Option<Box<Link<B>>>>,
+	block_import: SharedBlockImport<B>,
+	verifier: Arc<V>,
+	justification_import: Option<SharedJustificationImport<B>>,
+	finality_proof_import: Option<SharedFinalityProofImport<B>>,
+}
+
+impl<B: BlockT, V: Verifier<B>> BasicSyncQueue<B, V> {
+	pub fn new(
+		block_import: SharedBlockImport<B>,
+		verifier: Arc<V>,
+		justification_import: Option<SharedJustificationImport<B>>,
+		finality_proof_import: Option<SharedFinalityProofImport<B>>,
+	) -> Self {
+		BasicSyncQueue {
+			data: Arc::new(BasicSyncQueueData {
+				link: Mutex::new(None),
+				block_import,
+				verifier,
+				justification_import,
+				finality_proof_import,
+			}),
+		}
+	}
+}
+
+impl<B: BlockT, V: 'static + Verifier<B>> ImportQueue<B> for BasicSyncQueue<B, V> {
+	fn start(&self, link: Box<Link<B>>) -> Result<(), std::io::Error> {
+		if let Some(justification_import) = self.data.justification_import.as_ref() {
+			justification_import.on_start(&*link);
+		}
+		*self.data.link.lock() = Some(link);
+		Ok(())
+	}
+
+	fn import_blocks(&self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>) {
+		if blocks.is_empty() {
+			return;
+		}
+
+		let (imported, count, results) = import_many_blocks(
+			&*self.data.block_import,
+			origin,
+			blocks,
+			self.data.verifier.clone(),
+		);
+
+		let link_ref = self.data.link.lock();
+		let link = match link_ref.as_ref() {
+			Some(link) => link,
+			None => {
+				trace!(target: "sync", "Trying to import blocks before starting import queue");
+				return;
+			},
+		};
+
+		process_import_results(&**link, results);
+
+		trace!(target: "sync", "Imported {} of {}", imported, count);
+	}
+
+	fn import_justification(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, justification: Justification) {
+		import_single_justification(
+			&*self.data.link.lock(),
+			&self.data.justification_import,
+			who,
+			hash,
+			number,
+			justification,
+		)
+	}
+
+	fn import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>) {
+		let result = import_single_finality_proof(
+			&self.data.finality_proof_import,
+			&*self.data.verifier,
+			&who,
+			hash,
+			number,
+			finality_proof,
+		);
+		if let Some(link) = self.data.link.lock().as_ref() {
+			link.finality_proof_imported(who, (hash, number), result);
+		}
 	}
 }
 
@@ -129,16 +211,20 @@ impl<B: BlockT> Clone for Box<ImportQueue<B>> {
 /// sequentially in a separate thread, with pluggable verification.
 #[derive(Clone)]
 pub struct BasicQueue<B: BlockT> {
-	sender: Sender<BlockImportMsg<B>>,
+	sender: Option<Sender<BlockImportMsg<B>>>,
 }
 
-impl<B: BlockT> ImportQueueClone<B> for BasicQueue<B> {
-	fn clone_box(&self) -> Box<ImportQueue<B>> {
-		Box::new(self.clone())
+impl<B: BlockT> Drop for BasicQueue<B> {
+	fn drop(&mut self) {
+		if let Some(sender) = self.sender.take() {
+			let (shutdown_sender, shutdown_receiver) = channel::unbounded();
+			if sender.send(BlockImportMsg::Shutdown(shutdown_sender)).is_ok() {
+				let _ = shutdown_receiver.recv();
+			}
+		}
 	}
 }
 
-
 /// "BasicQueue" is a wrapper around a channel sender to the "BlockImporter".
 /// "BasicQueue" itself does not keep any state or do any importing work, and
 /// can therefore be send to other threads.
@@ -184,7 +270,7 @@ impl<B: BlockT> BasicQueue<B> {
 		);
 
 		Self {
-			sender: importer_sender,
+			sender: Some(importer_sender),
 		}
 	}
 
@@ -194,52 +280,47 @@ impl<B: BlockT> BasicQueue<B> {
 	/// has synchronized with ImportQueue.
 	#[cfg(any(test, feature = "test-helpers"))]
 	pub fn synchronize(&self) {
-		self
-			.sender
-			.send(BlockImportMsg::Synchronize)
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
+		if let Some(ref sender) = self.sender {
+			let _ = sender.send(BlockImportMsg::Synchronize);
+		}
 	}
 }
 
 impl<B: BlockT> ImportQueue<B> for BasicQueue<B> {
 	fn start(&self, link: Box<Link<B>>) -> Result<(), std::io::Error> {
-		let (sender, port) = channel::unbounded();
-		let _ = self
-			.sender
-			.send(BlockImportMsg::Start(link, sender))
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
-		port.recv().expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed")
-	}
-
-	fn stop(&self) {
-		let _ = self
-			.sender
-			.send(BlockImportMsg::Stop)
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
+		let connect_err = || Err(std::io::Error::new(
+			std::io::ErrorKind::Other,
+			"Failed to connect import queue threads",
+		));
+		if let Some(ref sender) = self.sender {
+			let (start_sender, start_port) = channel::unbounded();
+			let _ = sender.send(BlockImportMsg::Start(link, start_sender));
+			start_port.recv().unwrap_or_else(|_| connect_err())
+		} else {
+			connect_err()
+		}
 	}
 
 	fn import_blocks(&self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>) {
 		if blocks.is_empty() {
 			return;
 		}
-		let _ = self
-			.sender
-			.send(BlockImportMsg::ImportBlocks(origin, blocks))
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
+
+		if let Some(ref sender) = self.sender {
+			let _ = sender.send(BlockImportMsg::ImportBlocks(origin, blocks));
+		}
 	}
 
 	fn import_justification(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, justification: Justification) {
-		let _ = self
-			.sender
-			.send(BlockImportMsg::ImportJustification(who.clone(), hash, number, justification))
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
+		if let Some(ref sender) = self.sender {
+			let _ = sender.send(BlockImportMsg::ImportJustification(who.clone(), hash, number, justification));
+		}
 	}
 
 	fn import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>) {
-		let _ = self
-			.sender
-			.send(BlockImportMsg::ImportFinalityProof(who, hash, number, finality_proof))
-			.expect("1. self is holding a sender to the Importer, 2. Importer should handle messages while there are senders around; qed");
+		if let Some(ref sender) = self.sender {
+			let _ = sender.send(BlockImportMsg::ImportFinalityProof(who, hash, number, finality_proof));
+		}
 	}
 }
 
@@ -248,12 +329,12 @@ pub enum BlockImportMsg<B: BlockT> {
 	ImportJustification(Origin, B::Hash, NumberFor<B>, Justification),
 	ImportFinalityProof(Origin, B::Hash, NumberFor<B>, Vec<u8>),
 	Start(Box<Link<B>>, Sender<Result<(), std::io::Error>>),
-	Stop,
+	Shutdown(Sender<()>),
 	#[cfg(any(test, feature = "test-helpers"))]
 	Synchronize,
 }
 
-#[cfg_attr(test, derive(Debug, PartialEq))]
+#[cfg_attr(test, derive(Debug))]
 pub enum BlockImportWorkerMsg<B: BlockT> {
 	ImportBlocks(BlockOrigin, Vec<IncomingBlock<B>>),
 	ImportedBlocks(
@@ -264,6 +345,7 @@ pub enum BlockImportWorkerMsg<B: BlockT> {
 	),
 	ImportFinalityProof(Origin, B::Hash, NumberFor<B>, Vec<u8>),
 	ImportedFinalityProof(Origin, (B::Hash, NumberFor<B>), Result<(B::Hash, NumberFor<B>), ()>),
+	Shutdown(Sender<()>),
 	#[cfg(any(test, feature = "test-helpers"))]
 	Synchronize,
 }
@@ -276,7 +358,7 @@ enum ImportMsgType<B: BlockT> {
 struct BlockImporter<B: BlockT> {
 	port: Receiver<BlockImportMsg<B>>,
 	result_port: Receiver<BlockImportWorkerMsg<B>>,
-	worker_sender: Sender<BlockImportWorkerMsg<B>>,
+	worker_sender: Option<Sender<BlockImportWorkerMsg<B>>>,
 	link: Option<Box<dyn Link<B>>>,
 	verifier: Arc<Verifier<B>>,
 	justification_import: Option<SharedJustificationImport<B>>,
@@ -301,7 +383,7 @@ impl<B: BlockT> BlockImporter<B> {
 				let mut importer = BlockImporter {
 					port,
 					result_port,
-					worker_sender,
+					worker_sender: Some(worker_sender),
 					link: None,
 					verifier,
 					justification_import,
@@ -345,7 +427,14 @@ impl<B: BlockT> BlockImporter<B> {
 				self.handle_import_blocks(origin, incoming_blocks)
 			},
 			BlockImportMsg::ImportJustification(who, hash, number, justification) => {
-				self.handle_import_justification(who, hash, number, justification)
+				import_single_justification(
+					&self.link,
+					&self.justification_import,
+					who,
+					hash,
+					number,
+					justification,
+				);
 			},
 			BlockImportMsg::ImportFinalityProof(who, hash, number, finality_proof) => {
 				self.handle_import_finality_proof(who, hash, number, finality_proof)
@@ -363,13 +452,24 @@ impl<B: BlockT> BlockImporter<B> {
 				self.link = Some(link);
 				let _ = sender.send(Ok(()));
 			},
-			BlockImportMsg::Stop => return false,
+			BlockImportMsg::Shutdown(result_sender) => {
+				// stop worker thread
+				if let Some(worker_sender) = self.worker_sender.take() {
+					let (sender, receiver) = channel::unbounded();
+					if worker_sender.send(BlockImportWorkerMsg::Shutdown(sender)).is_ok() {
+						let _ = receiver.recv();
+					}
+				}
+				// send shutdown notification
+				let _ = result_sender.send(());
+				return false;
+			},
 			#[cfg(any(test, feature = "test-helpers"))]
 			BlockImportMsg::Synchronize => {
 				trace!(target: "sync", "Received synchronization message");
-				self.worker_sender
-					.send(BlockImportWorkerMsg::Synchronize)
-					.expect("1. This is holding a sender to the worker, 2. the worker should not quit while a sender is still held; qed");
+				if let Some(ref worker_sender) = self.worker_sender {
+					let _ = worker_sender.send(BlockImportWorkerMsg::Synchronize);
+				}
 			},
 		}
 		true
@@ -398,106 +498,26 @@ impl<B: BlockT> BlockImporter<B> {
 			},
 			BlockImportWorkerMsg::ImportBlocks(_, _)
 				| BlockImportWorkerMsg::ImportFinalityProof(_, _, _, _)
-					=> unreachable!("Import Worker does not send Import* message; qed"),
+				| BlockImportWorkerMsg::Shutdown(_)
+					=> unreachable!("Import Worker does not send Import*/Shutdown messages; qed"),
 		};
-		let mut has_error = false;
-		let mut hashes = vec![];
-		for (result, hash) in results {
-			hashes.push(hash);
 
-			if has_error {
-				continue;
-			}
-
-			if result.is_err() {
-				has_error = true;
-			}
-
-			match result {
-				Ok(BlockImportResult::ImportedKnown(number)) => link.block_imported(&hash, number),
-				Ok(BlockImportResult::ImportedUnknown(number, aux, who)) => {
-					link.block_imported(&hash, number);
-
-					if aux.clear_justification_requests {
-						trace!(target: "sync", "Block imported clears all pending justification requests {}: {:?}", number, hash);
-						link.clear_justification_requests();
-					}
-
-					if aux.needs_justification {
-						trace!(target: "sync", "Block imported but requires justification {}: {:?}", number, hash);
-						link.request_justification(&hash, number);
-					}
-
-					if aux.bad_justification {
-						if let Some(peer) = who {
-							info!("Sent block with bad justification to import");
-							link.report_peer(peer, BAD_JUSTIFICATION_REPUTATION_CHANGE);
-						}
-					}
-
-					if aux.needs_finality_proof {
-						trace!(target: "sync", "Block imported but requires finality proof {}: {:?}", number, hash);
-						link.request_finality_proof(&hash, number);
-					}
-				},
-				Err(BlockImportError::IncompleteHeader(who)) => {
-					if let Some(peer) = who {
-						info!("Peer sent block with incomplete header to import");
-						link.report_peer(peer, INCOMPLETE_HEADER_REPUTATION_CHANGE);
-						link.restart();
-					}
-				},
-				Err(BlockImportError::VerificationFailed(who, e)) => {
-					if let Some(peer) = who {
-						info!("Verification failed from peer: {}", e);
-						link.report_peer(peer, VERIFICATION_FAIL_REPUTATION_CHANGE);
-						link.restart();
-					}
-				},
-				Err(BlockImportError::BadBlock(who)) => {
-					if let Some(peer) = who {
-						info!("Bad block");
-						link.report_peer(peer, BAD_BLOCK_REPUTATION_CHANGE);
-						link.restart();
-					}
-				},
-				Err(BlockImportError::UnknownParent) | Err(BlockImportError::Error) => {
-					link.restart();
-				},
-			};
-		}
-		if let Some(link) = self.link.as_ref() {
-			link.blocks_processed(hashes, has_error);
-		}
+		process_import_results(&**link, results);
 		true
 	}
 
-	fn handle_import_justification(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, justification: Justification) {
-		let success = self.justification_import.as_ref().map(|justification_import| {
-			justification_import.import_justification(hash, number, justification)
-				.map_err(|e| {
-					debug!(target: "sync", "Justification import failed with {:?} for hash: {:?} number: {:?} coming from node: {:?}", e, hash, number, who);
-					e
-				}).is_ok()
-		}).unwrap_or(false);
-
-		if let Some(link) = self.link.as_ref() {
-			link.justification_imported(who, &hash, number, success);
+	fn handle_import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>) {
+		if let Some(ref worker_sender) = self.worker_sender {
+			trace!(target: "sync", "Scheduling finality proof of {}/{} for import", number, hash);
+			let _ = worker_sender.send(BlockImportWorkerMsg::ImportFinalityProof(who, hash, number, finality_proof));
 		}
 	}
 
-	fn handle_import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>) {
-		trace!(target: "sync", "Scheduling finality proof of {}/{} for import", number, hash);
-		self.worker_sender
-			.send(BlockImportWorkerMsg::ImportFinalityProof(who, hash, number, finality_proof))
-			.expect("1. This is holding a sender to the worker, 2. the worker should not quit while a sender is still held; qed");
-	}
-
 	fn handle_import_blocks(&mut self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>) {
-		trace!(target: "sync", "Scheduling {} blocks for import", blocks.len());
-		self.worker_sender
-			.send(BlockImportWorkerMsg::ImportBlocks(origin, blocks))
-			.expect("1. This is holding a sender to the worker, 2. the worker should not quit while a sender is still held; qed");
+		if let Some(ref worker_sender) = self.worker_sender {
+			trace!(target: "sync", "Scheduling {} blocks for import", blocks.len());
+			let _ = worker_sender.send(BlockImportWorkerMsg::ImportBlocks(origin, blocks));
+		}
 	}
 }
 
@@ -534,6 +554,10 @@ impl<B: BlockT, V: 'static + Verifier<B>> BlockImportWorker<B, V> {
 						BlockImportWorkerMsg::ImportFinalityProof(who, hash, number, proof) => {
 							worker.import_finality_proof(who, hash, number, proof);
 						},
+						BlockImportWorkerMsg::Shutdown(result_sender) => {
+							let _ = result_sender.send(());
+							break;
+						},
 						#[cfg(any(test, feature = "test-helpers"))]
 						BlockImportWorkerMsg::Synchronize => {
 							trace!(target: "sync", "Sending sync message");
@@ -550,44 +574,12 @@ impl<B: BlockT, V: 'static + Verifier<B>> BlockImportWorker<B, V> {
 	}
 
 	fn import_a_batch_of_blocks(&self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>) {
-		let count = blocks.len();
-		let mut imported = 0;
-
-		let blocks_range = match (
-			blocks.first().and_then(|b| b.header.as_ref().map(|h| h.number())),
-			blocks.last().and_then(|b| b.header.as_ref().map(|h| h.number())),
-		) {
-			(Some(first), Some(last)) if first != last => format!(" ({}..{})", first, last),
-			(Some(first), Some(_)) => format!(" ({})", first),
-			_ => Default::default(),
-		};
-
-		trace!(target: "sync", "Starting import of {} blocks {}", count, blocks_range);
-
-		let mut results = vec![];
-
-		let mut has_error = false;
-
-		// Blocks in the response/drain should be in ascending order.
-		for block in blocks {
-			let import_result = if has_error {
-				Err(BlockImportError::Error)
-			} else {
-				import_single_block(
-					&*self.block_import,
-					origin.clone(),
-					block.clone(),
-					self.verifier.clone(),
-				)
-			};
-			let was_ok = import_result.is_ok();
-			results.push((import_result, block.hash));
-			if was_ok {
-				imported += 1;
-			} else {
-				has_error = true;
-			}
-		}
+		let (imported, count, results) = import_many_blocks(
+			&*self.block_import,
+			origin,
+			blocks,
+			self.verifier.clone(),
+		);
 
 		let _ = self
 			.result_sender
@@ -597,24 +589,18 @@ impl<B: BlockT, V: 'static + Verifier<B>> BlockImportWorker<B, V> {
 	}
 
 	fn import_finality_proof(&self, who: Origin, hash: B::Hash, number: NumberFor<B>, finality_proof: Vec<u8>) {
-		let result = self.finality_proof_import.as_ref().map(|finality_proof_import| {
-			finality_proof_import.import_finality_proof(hash, number, finality_proof, &*self.verifier)
-				.map_err(|e| {
-					debug!(
-						"Finality proof import failed with {:?} for hash: {:?} number: {:?} coming from node: {:?}",
-						e,
-						hash,
-						number,
-						who,
-					);
-				})
-		}).unwrap_or(Err(()));
+		let result = import_single_finality_proof(
+			&self.finality_proof_import,
+			&*self.verifier,
+			&who,
+			hash,
+			number,
+			finality_proof,
+		);
 
 		let _ = self
 			.result_sender
 			.send(BlockImportWorkerMsg::ImportedFinalityProof(who, (hash, number), result));
-
-		trace!(target: "sync", "Imported finality proof for {}/{}", number, hash);
 	}
 }
 
@@ -679,6 +665,193 @@ pub enum BlockImportError {
 	Error,
 }
 
+/// Imports single notification and send notification to the link (if provided).
+fn import_single_justification<B: BlockT>(
+	link: &Option<Box<Link<B>>>,
+	justification_import: &Option<SharedJustificationImport<B>>,
+	who: Origin,
+	hash: B::Hash,
+	number: NumberFor<B>,
+	justification: Justification,
+) {
+	let success = justification_import.as_ref().map(|justification_import| {
+		justification_import.import_justification(hash, number, justification)
+			.map_err(|e| {
+				debug!(
+					target: "sync",
+					"Justification import failed with {:?} for hash: {:?} number: {:?} coming from node: {:?}",
+					e,
+					hash,
+					number,
+					who,
+				);
+				e
+			}).is_ok()
+	}).unwrap_or(false);
+
+	if let Some(ref link) = link {
+		link.justification_imported(who, &hash, number, success);
+	}
+}
+
+/// Imports single finality_proof.
+fn import_single_finality_proof<B: BlockT, V: Verifier<B>>(
+	finality_proof_import: &Option<SharedFinalityProofImport<B>>,
+	verifier: &V,
+	who: &Origin,
+	hash: B::Hash,
+	number: NumberFor<B>,
+	finality_proof: Vec<u8>,
+) -> Result<(B::Hash, NumberFor<B>), ()> {
+	let result = finality_proof_import.as_ref().map(|finality_proof_import| {
+		finality_proof_import.import_finality_proof(hash, number, finality_proof, verifier)
+			.map_err(|e| {
+				debug!(
+					"Finality proof import failed with {:?} for hash: {:?} number: {:?} coming from node: {:?}",
+					e,
+					hash,
+					number,
+					who,
+				);
+			})
+	}).unwrap_or(Err(()));
+
+	trace!(target: "sync", "Imported finality proof for {}/{}", number, hash);
+
+	result
+}
+
+/// Process result of block(s) import.
+fn process_import_results<B: BlockT>(
+	link: &Link<B>,
+	results: Vec<(
+		Result<BlockImportResult<NumberFor<B>>, BlockImportError>,
+		B::Hash,
+	)>,
+)
+{
+	let mut has_error = false;
+	let mut hashes = vec![];
+	for (result, hash) in results {
+		hashes.push(hash);
+
+		if has_error {
+			continue;
+		}
+
+		if result.is_err() {
+			has_error = true;
+		}
+
+		match result {
+			Ok(BlockImportResult::ImportedKnown(number)) => link.block_imported(&hash, number),
+			Ok(BlockImportResult::ImportedUnknown(number, aux, who)) => {
+				link.block_imported(&hash, number);
+
+				if aux.clear_justification_requests {
+					trace!(target: "sync", "Block imported clears all pending justification requests {}: {:?}", number, hash);
+					link.clear_justification_requests();
+				}
+
+				if aux.needs_justification {
+					trace!(target: "sync", "Block imported but requires justification {}: {:?}", number, hash);
+					link.request_justification(&hash, number);
+				}
+
+				if aux.bad_justification {
+					if let Some(peer) = who {
+						info!("Sent block with bad justification to import");
+						link.report_peer(peer, BAD_JUSTIFICATION_REPUTATION_CHANGE);
+					}
+				}
+
+				if aux.needs_finality_proof {
+					trace!(target: "sync", "Block imported but requires finality proof {}: {:?}", number, hash);
+					link.request_finality_proof(&hash, number);
+				}
+			},
+			Err(BlockImportError::IncompleteHeader(who)) => {
+				if let Some(peer) = who {
+					info!("Peer sent block with incomplete header to import");
+					link.report_peer(peer, INCOMPLETE_HEADER_REPUTATION_CHANGE);
+					link.restart();
+				}
+			},
+			Err(BlockImportError::VerificationFailed(who, e)) => {
+				if let Some(peer) = who {
+					info!("Verification failed from peer: {}", e);
+					link.report_peer(peer, VERIFICATION_FAIL_REPUTATION_CHANGE);
+					link.restart();
+				}
+			},
+			Err(BlockImportError::BadBlock(who)) => {
+				if let Some(peer) = who {
+					info!("Bad block");
+					link.report_peer(peer, BAD_BLOCK_REPUTATION_CHANGE);
+					link.restart();
+				}
+			},
+			Err(BlockImportError::UnknownParent) | Err(BlockImportError::Error) => {
+				link.restart();
+			},
+		};
+	}
+	link.blocks_processed(hashes, has_error);
+}
+
+/// Import several blocks at once, returning import result for each block.
+fn import_many_blocks<B: BlockT, V: Verifier<B>>(
+	import_handle: &BlockImport<B, Error = ConsensusError>,
+	blocks_origin: BlockOrigin,
+	blocks: Vec<IncomingBlock<B>>,
+	verifier: Arc<V>,
+) -> (usize, usize, Vec<(
+	Result<BlockImportResult<NumberFor<B>>, BlockImportError>,
+	B::Hash,
+)>) {
+	let count = blocks.len();
+	let mut imported = 0;
+
+	let blocks_range = match (
+		blocks.first().and_then(|b| b.header.as_ref().map(|h| h.number())),
+		blocks.last().and_then(|b| b.header.as_ref().map(|h| h.number())),
+	) {
+		(Some(first), Some(last)) if first != last => format!(" ({}..{})", first, last),
+		(Some(first), Some(_)) => format!(" ({})", first),
+		_ => Default::default(),
+	};
+
+	trace!(target: "sync", "Starting import of {} blocks {}", count, blocks_range);
+
+	let mut results = vec![];
+
+	let mut has_error = false;
+
+	// Blocks in the response/drain should be in ascending order.
+	for block in blocks {
+		let block_hash = block.hash;
+		let import_result = if has_error {
+			Err(BlockImportError::Error)
+		} else {
+			import_single_block(
+				import_handle,
+				blocks_origin.clone(),
+				block,
+				verifier.clone(),
+			)
+		};
+		let was_ok = import_result.is_ok();
+		results.push((import_result, block_hash));
+		if was_ok {
+			imported += 1;
+		} else {
+			has_error = true;
+		}
+	}
+
+	(imported, count, results)
+}
+
 /// Single block import function.
 pub fn import_single_block<B: BlockT, V: Verifier<B>>(
 	import_handle: &BlockImport<B, Error = ConsensusError>,
@@ -909,12 +1082,19 @@ mod tests {
 		)).unwrap();
 
 		// Wait until this request is redirected to the BlockImportWorker
-		assert_eq!(worker_receiver.recv(), Ok(BlockImportWorkerMsg::ImportFinalityProof(
-			who.clone(),
-			Default::default(),
-			1,
-			vec![42],
-		)));
+		match worker_receiver.recv().unwrap() {
+			BlockImportWorkerMsg::ImportFinalityProof(
+				cwho,
+				chash,
+				1,
+				cproof,
+			) => {
+				assert_eq!(cwho, who);
+				assert_eq!(chash, Default::default());
+				assert_eq!(cproof, vec![42]);
+			},
+			_ => unreachable!("Unexpected work request received"),
+		}
 
 		// Send ack of proof import from BlockImportWorker to BlockImporter
 		result_sender.send(BlockImportWorkerMsg::ImportedFinalityProof(
diff --git a/substrate/core/network/src/service.rs b/substrate/core/network/src/service.rs
index b2e56a83bd..c8679c96f7 100644
--- a/substrate/core/network/src/service.rs
+++ b/substrate/core/network/src/service.rs
@@ -211,6 +211,14 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>> Service<B, S> {
 		let (network_chan, network_port) = mpsc::unbounded();
 		let (protocol_sender, protocol_rx) = mpsc::unbounded();
 		let status_sinks = Arc::new(Mutex::new(Vec::new()));
+
+		// connect the import-queue to the network service.
+		let link = NetworkLink {
+			protocol_sender: protocol_sender.clone(),
+			network_sender: network_chan.clone(),
+		};
+		import_queue.start(Box::new(link))?;
+
 		// Start in off-line mode, since we're not connected to any nodes yet.
 		let is_offline = Arc::new(AtomicBool::new(true));
 		let is_major_syncing = Arc::new(AtomicBool::new(false));
@@ -229,7 +237,7 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>> Service<B, S> {
 			is_major_syncing.clone(),
 			protocol,
 			peers.clone(),
-			import_queue.clone(),
+			import_queue,
 			params.transaction_pool,
 			params.finality_proof_provider,
 			network_port,
@@ -244,22 +252,14 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>> Service<B, S> {
 			status_sinks,
 			is_offline,
 			is_major_syncing,
-			network_chan: network_chan.clone(),
+			network_chan,
 			peers,
 			peerset,
 			network,
-			protocol_sender: protocol_sender.clone(),
+			protocol_sender,
 			bg_thread: Some(thread),
 		});
 
-		// connect the import-queue to the network service.
-		let link = NetworkLink {
-			protocol_sender,
-			network_sender: network_chan,
-		};
-
-		import_queue.start(Box::new(link))?;
-
 		Ok(service)
 	}