diff --git a/substrate/client/basic-authorship/src/basic_authorship.rs b/substrate/client/basic-authorship/src/basic_authorship.rs
index 5a020ee810..b67008bc6f 100644
--- a/substrate/client/basic-authorship/src/basic_authorship.rs
+++ b/substrate/client/basic-authorship/src/basic_authorship.rs
@@ -20,7 +20,7 @@
 
 // FIXME #1021 move this into sp-consensus
 
-use codec::{Decode, Encode};
+use codec::Encode;
 use futures::{
 	channel::oneshot,
 	future,
@@ -536,10 +536,6 @@ where
 			"hash" => ?<Block as BlockT>::Hash::from(block.header().hash()),
 		);
 
-		if Decode::decode(&mut block.encode().as_slice()).as_ref() != Ok(&block) {
-			error!("Failed to verify block encoding/decoding");
-		}
-
 		if let Err(err) =
 			evaluation::evaluate_initial(&block, &self.parent_hash, self.parent_number)
 		{
diff --git a/substrate/primitives/consensus/common/src/evaluation.rs b/substrate/primitives/consensus/common/src/evaluation.rs
index 6a6ca835f3..d1ce8e9fc5 100644
--- a/substrate/primitives/consensus/common/src/evaluation.rs
+++ b/substrate/primitives/consensus/common/src/evaluation.rs
@@ -30,6 +30,8 @@ pub type Result<T> = std::result::Result<T, Error>;
 /// Error type.
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
+	#[error("Failed to verify block encoding/decoding")]
+	BadBlockCodec,
 	/// Proposal provided not a block.
 	#[error("Proposal provided not a block: decoding error: {0}")]
 	BadProposalFormat(#[from] codec::Error),
@@ -49,19 +51,22 @@ pub fn evaluate_initial<Block: BlockT>(
 	parent_number: <<Block as BlockT>::Header as HeaderT>::Number,
 ) -> Result<()> {
 	let encoded = Encode::encode(proposal);
-	let proposal = Block::decode(&mut &encoded[..]).map_err(Error::BadProposalFormat)?;
+	let block = Block::decode(&mut &encoded[..]).map_err(Error::BadProposalFormat)?;
+	if &block != proposal {
+		return Err(Error::BadBlockCodec)
+	}
 
-	if *parent_hash != *proposal.header().parent_hash() {
+	if *parent_hash != *block.header().parent_hash() {
 		return Err(Error::WrongParentHash {
 			expected: format!("{:?}", *parent_hash),
-			got: format!("{:?}", proposal.header().parent_hash()),
+			got: format!("{:?}", block.header().parent_hash()),
 		})
 	}
 
-	if parent_number + One::one() != *proposal.header().number() {
+	if parent_number + One::one() != *block.header().number() {
 		return Err(Error::WrongNumber {
 			expected: parent_number.checked_into::<u128>().map(|x| x + 1),
-			got: (*proposal.header().number()).checked_into::<u128>(),
+			got: (*block.header().number()).checked_into::<u128>(),
 		})
 	}