diff --git a/substrate/core/network/src/protocol.rs b/substrate/core/network/src/protocol.rs
index 88252d7786..b561322b5b 100644
--- a/substrate/core/network/src/protocol.rs
+++ b/substrate/core/network/src/protocol.rs
@@ -442,6 +442,11 @@ impl<B: BlockT, S: NetworkSpecialization<B>, H: ExHashT> Protocol<B, S, H> {
 		self.sync.status().num_peers
 	}
 
+	/// Number of blocks in the import queue.
+	pub fn num_queued_blocks(&self) -> u32 {
+		self.sync.status().queued_blocks
+	}
+
 	/// Starts a new data demand request.
 	///
 	/// The parameter contains a `Sender` where the result, once received, must be sent.
diff --git a/substrate/core/network/src/protocol/sync.rs b/substrate/core/network/src/protocol/sync.rs
index 12f0ac6568..80b0662c6b 100644
--- a/substrate/core/network/src/protocol/sync.rs
+++ b/substrate/core/network/src/protocol/sync.rs
@@ -198,7 +198,9 @@ pub struct Status<B: BlockT> {
 	/// Target sync block number.
 	pub best_seen_block: Option<NumberFor<B>>,
 	/// Number of peers participating in syncing.
-	pub num_peers: u32
+	pub num_peers: u32,
+	/// Number of blocks queued for import
+	pub queued_blocks: u32,
 }
 
 /// A peer did not behave as expected and should be reported.
@@ -317,7 +319,8 @@ impl<B: BlockT> ChainSync<B> {
 		Status {
 			state: sync_state,
 			best_seen_block: best_seen,
-			num_peers: self.peers.len() as u32
+			num_peers: self.peers.len() as u32,
+			queued_blocks: self.queue_blocks.len() as u32,
 		}
 	}
 
diff --git a/substrate/core/network/src/service.rs b/substrate/core/network/src/service.rs
index ff5db5f702..eed5de85ed 100644
--- a/substrate/core/network/src/service.rs
+++ b/substrate/core/network/src/service.rs
@@ -280,6 +280,11 @@ impl<B: BlockT + 'static, S: NetworkSpecialization<B>, H: ExHashT> NetworkWorker
 		self.network_service.user_protocol().num_sync_peers()
 	}
 
+	/// Number of blocks in the import queue.
+	pub fn num_queued_blocks(&self) -> u32 {
+		self.network_service.user_protocol().num_queued_blocks()
+	}
+
 	/// Adds an address for a node.
 	pub fn add_known_address(&mut self, peer_id: PeerId, addr: Multiaddr) {
 		self.network_service.add_known_address(peer_id, addr);
diff --git a/substrate/core/network/src/test/mod.rs b/substrate/core/network/src/test/mod.rs
index f12b4c8237..091047394b 100644
--- a/substrate/core/network/src/test/mod.rs
+++ b/substrate/core/network/src/test/mod.rs
@@ -591,6 +591,9 @@ pub trait TestNetFactory: Sized {
 		// Return `NotReady` if there's a mismatch in the highest block number.
 		let mut highest = None;
 		for peer in self.peers().iter() {
+			if peer.is_major_syncing() || peer.network.num_queued_blocks() != 0 {
+				return Async::NotReady
+			}
 			match (highest, peer.client.info().chain.best_number) {
 				(None, b) => highest = Some(b),
 				(Some(ref a), ref b) if a == b => {},