diff --git a/node/core/runtime-api/src/cache.rs b/node/core/runtime-api/src/cache.rs
index 9c3aeaa8d819..2a172195510e 100644
--- a/node/core/runtime-api/src/cache.rs
+++ b/node/core/runtime-api/src/cache.rs
@@ -21,7 +21,7 @@ use parity_util_mem::{MallocSizeOf, MallocSizeOfExt};
 use sp_consensus_babe::Epoch;
 
 use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, BlockNumber, CandidateCommitments, CandidateEvent,
+	AuthorityDiscoveryId, BlockNumber, CandidateCommitments, CandidateEvent, CandidateHash,
 	CommittedCandidateReceipt, CoreState, GroupRotationInfo, Hash, Id as ParaId,
 	InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption, PersistedValidationData,
 	ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode, ValidationCodeHash,
@@ -43,6 +43,8 @@ const DMQ_CONTENTS_CACHE_SIZE: usize = 64 * 1024;
 const INBOUND_HRMP_CHANNELS_CACHE_SIZE: usize = 64 * 1024;
 const CURRENT_BABE_EPOCH_CACHE_SIZE: usize = 64 * 1024;
 const ON_CHAIN_VOTES_CACHE_SIZE: usize = 3 * 1024;
+/// Seems plenty, considering that we are only storing block numbers here:
+const CANDIDATES_INCLUDED_STATE_CACHE_SIZE: usize = 1024;
 
 struct ResidentSizeOf<T>(T);
 
@@ -101,6 +103,8 @@ pub(crate) struct RequestResultCache {
 	>,
 	current_babe_epoch: MemoryLruCache<Hash, DoesNotAllocate<Epoch>>,
 	on_chain_votes: MemoryLruCache<Hash, ResidentSizeOf<Option<ScrapedOnChainVotes>>>,
+	candidates_included_state:
+		MemoryLruCache<(Hash, SessionIndex, CandidateHash), ResidentSizeOf<Option<BlockNumber>>>,
 }
 
 impl Default for RequestResultCache {
@@ -124,6 +128,7 @@ impl Default for RequestResultCache {
 			inbound_hrmp_channels_contents: MemoryLruCache::new(INBOUND_HRMP_CHANNELS_CACHE_SIZE),
 			current_babe_epoch: MemoryLruCache::new(CURRENT_BABE_EPOCH_CACHE_SIZE),
 			on_chain_votes: MemoryLruCache::new(ON_CHAIN_VOTES_CACHE_SIZE),
+			candidates_included_state: MemoryLruCache::new(CANDIDATES_INCLUDED_STATE_CACHE_SIZE),
 		}
 	}
 }
@@ -332,6 +337,13 @@ impl RequestResultCache {
 		self.on_chain_votes.get(relay_parent).map(|v| &v.0)
 	}
 
+	pub(crate) fn candidate_included_state(
+		&mut self,
+		key: (Hash, SessionIndex, CandidateHash),
+	) -> Option<&Option<BlockNumber>> {
+		self.candidates_included_state.get(&key).map(|v| &v.0)
+	}
+
 	pub(crate) fn cache_on_chain_votes(
 		&mut self,
 		relay_parent: Hash,
@@ -339,6 +351,13 @@ impl RequestResultCache {
 	) {
 		self.on_chain_votes.insert(relay_parent, ResidentSizeOf(scraped));
 	}
+	pub(crate) fn cache_candidate_included_state(
+		&mut self,
+		key: (Hash, SessionIndex, CandidateHash),
+		included: Option<BlockNumber>,
+	) {
+		self.candidates_included_state.insert(key, ResidentSizeOf(included));
+	}
 }
 
 pub(crate) enum RequestResult {
@@ -362,4 +381,5 @@ pub(crate) enum RequestResult {
 	),
 	CurrentBabeEpoch(Hash, Epoch),
 	FetchOnChainVotes(Hash, Option<ScrapedOnChainVotes>),
+	CandidateIncludedState(Hash, SessionIndex, CandidateHash, Option<BlockNumber>),
 }
diff --git a/node/core/runtime-api/src/lib.rs b/node/core/runtime-api/src/lib.rs
index a24192c2c54f..7788004ea535 100644
--- a/node/core/runtime-api/src/lib.rs
+++ b/node/core/runtime-api/src/lib.rs
@@ -145,6 +145,11 @@ where
 				self.requests_cache.cache_current_babe_epoch(relay_parent, epoch),
 			FetchOnChainVotes(relay_parent, scraped) =>
 				self.requests_cache.cache_on_chain_votes(relay_parent, scraped),
+			CandidateIncludedState(relay_parent, session_index, candidate_hash, block_number) =>
+				self.requests_cache.cache_candidate_included_state(
+					(relay_parent, session_index, candidate_hash),
+					block_number,
+				),
 		}
 	}
 
@@ -213,6 +218,10 @@ where
 				query!(current_babe_epoch(), sender).map(|sender| Request::CurrentBabeEpoch(sender)),
 			Request::FetchOnChainVotes(sender) =>
 				query!(on_chain_votes(), sender).map(|sender| Request::FetchOnChainVotes(sender)),
+			Request::CandidateIncludedState(session_index, candidate_hash, sender) =>
+				query!(candidate_included_state(session_index, candidate_hash), sender).map(
+					|sender| Request::CandidateIncludedState(session_index, candidate_hash, sender),
+				),
 		}
 	}
 
@@ -347,6 +356,11 @@ where
 			query!(InboundHrmpChannelsContents, inbound_hrmp_channels_contents(id), sender),
 		Request::CurrentBabeEpoch(sender) => query!(CurrentBabeEpoch, current_epoch(), sender),
 		Request::FetchOnChainVotes(sender) => query!(FetchOnChainVotes, on_chain_votes(), sender),
+		Request::CandidateIncludedState(session_index, candidate_hash, sender) => query!(
+			CandidateIncludedState,
+			candidate_included_state(session_index, candidate_hash),
+			sender
+		),
 	}
 }
 
diff --git a/node/core/runtime-api/src/tests.rs b/node/core/runtime-api/src/tests.rs
index 983aa7d89e20..fe87ec0a5f57 100644
--- a/node/core/runtime-api/src/tests.rs
+++ b/node/core/runtime-api/src/tests.rs
@@ -20,10 +20,10 @@ use futures::channel::oneshot;
 use polkadot_node_primitives::{BabeAllowedSlots, BabeEpoch, BabeEpochConfiguration};
 use polkadot_node_subsystem_test_helpers as test_helpers;
 use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState, GroupRotationInfo,
-	Id as ParaId, InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption,
-	PersistedValidationData, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode,
-	ValidationCodeHash, ValidatorId, ValidatorIndex,
+	AuthorityDiscoveryId, BlockNumber, CandidateEvent, CandidateHash, CommittedCandidateReceipt,
+	CoreState, GroupRotationInfo, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
+	OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes, SessionIndex,
+	SessionInfo, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
 };
 use sp_core::testing::TaskExecutor;
 use std::{
@@ -50,6 +50,7 @@ struct MockRuntimeApi {
 	hrmp_channels: HashMap<ParaId, BTreeMap<ParaId, Vec<InboundHrmpMessage>>>,
 	babe_epoch: Option<BabeEpoch>,
 	on_chain_votes: Option<ScrapedOnChainVotes>,
+	candidates_included_state: HashMap<(SessionIndex, CandidateHash), BlockNumber>,
 }
 
 impl ProvideRuntimeApi<Block> for MockRuntimeApi {
@@ -154,6 +155,10 @@ sp_api::mock_impl_runtime_apis! {
 		fn on_chain_votes(&self) -> Option<ScrapedOnChainVotes> {
 			self.on_chain_votes.clone()
 		}
+
+		fn candidate_included_state(session_index: SessionIndex, candidate_hash: CandidateHash) -> Option<BlockNumber> {
+			self.candidates_included_state.get(&(session_index, candidate_hash)).cloned()
+		}
 	}
 
 	impl BabeApi<Block> for MockRuntimeApi {
@@ -221,6 +226,44 @@ fn requests_authorities() {
 	futures::executor::block_on(future::join(subsystem_task, test_task));
 }
 
+#[test]
+fn request_included_state() {
+	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+
+	let mut runtime_api = MockRuntimeApi::default();
+	let candidate_hash = CandidateHash(Hash::repeat_byte(0xaa));
+	let session_index = 1;
+	let included_block = 8_u32;
+	runtime_api
+		.candidates_included_state
+		.insert((session_index, candidate_hash.clone()), included_block);
+	let runtime_api = Arc::new(runtime_api);
+
+	let relay_parent = [1; 32].into();
+	let spawner = sp_core::testing::TaskExecutor::new();
+
+	let subsystem = RuntimeApiSubsystem::new(runtime_api.clone(), Metrics(None), spawner);
+	let subsystem_task = run(ctx, subsystem).map(|x| x.unwrap());
+	let test_task = async move {
+		let (tx, rx) = oneshot::channel();
+
+		ctx_handle
+			.send(FromOverseer::Communication {
+				msg: RuntimeApiMessage::Request(
+					relay_parent,
+					Request::CandidateIncludedState(session_index, candidate_hash, tx),
+				),
+			})
+			.await;
+
+		assert_eq!(rx.await.unwrap().unwrap(), Some(included_block));
+
+		ctx_handle.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
+	};
+
+	futures::executor::block_on(future::join(subsystem_task, test_task));
+}
+
 #[test]
 fn requests_validators() {
 	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
diff --git a/node/subsystem-types/src/messages.rs b/node/subsystem-types/src/messages.rs
index f9c739f9dbdf..bdaa9d5e3f62 100644
--- a/node/subsystem-types/src/messages.rs
+++ b/node/subsystem-types/src/messages.rs
@@ -645,6 +645,8 @@ pub enum RuntimeApiRequest {
 	CurrentBabeEpoch(RuntimeApiSender<BabeEpoch>),
 	/// Get all disputes in relation to a relay parent.
 	FetchOnChainVotes(RuntimeApiSender<Option<polkadot_primitives::v1::ScrapedOnChainVotes>>),
+	/// Get included state for a particular candidate and session number.
+	CandidateIncludedState(SessionIndex, CandidateHash, RuntimeApiSender<Option<BlockNumber>>),
 }
 
 /// A message to the Runtime API subsystem.
diff --git a/primitives/Cargo.toml b/primitives/Cargo.toml
index 4aa5d00a3a7c..4a444ed069bc 100644
--- a/primitives/Cargo.toml
+++ b/primitives/Cargo.toml
@@ -56,3 +56,4 @@ std = [
 	"bitvec/std",
 	"frame-system/std",
 ]
+disputes = []
diff --git a/primitives/src/v1/mod.rs b/primitives/src/v1/mod.rs
index cbea6480efef..0d033dc8fda0 100644
--- a/primitives/src/v1/mod.rs
+++ b/primitives/src/v1/mod.rs
@@ -1036,6 +1036,10 @@ sp_api::decl_runtime_apis! {
 
 		/// Scrape dispute relevant from on-chain, backing votes and resolved disputes.
 		fn on_chain_votes() -> Option<ScrapedOnChainVotes<H>>;
+
+		/// Get included state of a given candidate as known to the disputes module.
+		#[cfg(feature = "disputes")]
+		fn candidate_included_state(session_index: SessionIndex, candidate_hash: CandidateHash) -> Option<BlockNumber>;
 	}
 }
 
diff --git a/runtime/parachains/src/disputes.rs b/runtime/parachains/src/disputes.rs
index 1ec5515667fb..3bc0a24ef025 100644
--- a/runtime/parachains/src/disputes.rs
+++ b/runtime/parachains/src/disputes.rs
@@ -1113,6 +1113,14 @@ impl<T: Config> Pallet<T> {
 		}
 	}
 
+	/// Retrieve the included state of a given candidate in a particular session.
+	pub(crate) fn get_included_state(
+		session: &SessionIndex,
+		candidate_hash: &CandidateHash,
+	) -> Option<T::BlockNumber> {
+		<Included<T>>::get(session, candidate_hash)
+	}
+
 	pub(crate) fn concluded_invalid(session: SessionIndex, candidate_hash: CandidateHash) -> bool {
 		<Disputes<T>>::get(&session, &candidate_hash).map_or(false, |dispute| {
 			// A dispute that has concluded with supermajority-against.
diff --git a/runtime/parachains/src/runtime_api_impl/v1.rs b/runtime/parachains/src/runtime_api_impl/v1.rs
index 5909ea55290b..0ee81a479b41 100644
--- a/runtime/parachains/src/runtime_api_impl/v1.rs
+++ b/runtime/parachains/src/runtime_api_impl/v1.rs
@@ -18,12 +18,12 @@
 //! functions.
 
 use crate::{
-	configuration, dmp, hrmp, inclusion, initializer, paras, paras_inherent, scheduler,
+	configuration, disputes, dmp, hrmp, inclusion, initializer, paras, paras_inherent, scheduler,
 	session_info, shared,
 };
 use primitives::v1::{
-	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreIndex, CoreOccupied,
-	CoreState, GroupIndex, GroupRotationInfo, Id as ParaId, InboundDownwardMessage,
+	AuthorityDiscoveryId, CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreIndex,
+	CoreOccupied, CoreState, GroupIndex, GroupRotationInfo, Id as ParaId, InboundDownwardMessage,
 	InboundHrmpMessage, OccupiedCore, OccupiedCoreAssumption, PersistedValidationData,
 	ScheduledCore, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode,
 	ValidationCodeHash, ValidatorId, ValidatorIndex,
@@ -335,3 +335,11 @@ pub fn validation_code_by_hash<T: paras::Config>(
 pub fn on_chain_votes<T: paras_inherent::Config>() -> Option<ScrapedOnChainVotes<T::Hash>> {
 	<paras_inherent::Pallet<T>>::on_chain_votes()
 }
+
+/// Query candidate included state.
+pub fn candidate_included_state<T: disputes::Config>(
+	session_index: SessionIndex,
+	candidate_hash: CandidateHash,
+) -> Option<T::BlockNumber> {
+	<disputes::Pallet<T>>::get_included_state(&session_index, &candidate_hash)
+}
diff --git a/runtime/rococo/Cargo.toml b/runtime/rococo/Cargo.toml
index 294cb062a225..19d8ea64e78f 100644
--- a/runtime/rococo/Cargo.toml
+++ b/runtime/rococo/Cargo.toml
@@ -60,7 +60,7 @@ frame-system = { git = "https://github.com/paritytech/substrate", branch = "mast
 frame-system-rpc-runtime-api = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 
 runtime-common = { package = "polkadot-runtime-common", path = "../common", default-features = false }
-primitives = { package = "polkadot-primitives", path = "../../primitives", default-features = false }
+primitives = { package = "polkadot-primitives", path = "../../primitives", default-features = false, features = [ "disputes" ] }
 polkadot-parachain = { path = "../../parachain", default-features = false }
 runtime-parachains = { package = "polkadot-runtime-parachains", path = "../parachains", default-features = false }
 
diff --git a/runtime/rococo/src/lib.rs b/runtime/rococo/src/lib.rs
index a7d1014f10c9..e92f56941c11 100644
--- a/runtime/rococo/src/lib.rs
+++ b/runtime/rococo/src/lib.rs
@@ -36,11 +36,11 @@ use pallet_session::historical as session_historical;
 use pallet_transaction_payment::{CurrencyAdapter, FeeDetails, RuntimeDispatchInfo};
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
 use primitives::v1::{
-	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CommittedCandidateReceipt,
-	CoreState, GroupRotationInfo, Hash, Id, InboundDownwardMessage, InboundHrmpMessage, Moment,
-	Nonce, OccupiedCoreAssumption, PersistedValidationData, ScrapedOnChainVotes,
-	SessionInfo as SessionInfoData, Signature, ValidationCode, ValidationCodeHash, ValidatorId,
-	ValidatorIndex,
+	AccountId, AccountIndex, Balance, BlockNumber, CandidateEvent, CandidateHash,
+	CommittedCandidateReceipt, CoreState, GroupRotationInfo, Hash, Id, InboundDownwardMessage,
+	InboundHrmpMessage, Moment, Nonce, OccupiedCoreAssumption, PersistedValidationData,
+	ScrapedOnChainVotes, SessionInfo as SessionInfoData, Signature, ValidationCode,
+	ValidationCodeHash, ValidatorId, ValidatorIndex,
 };
 use runtime_common::{
 	auctions, crowdloan, impls::ToAuthor, paras_registrar, paras_sudo_wrapper, slots, xcm_sender,
@@ -1290,6 +1290,10 @@ sp_api::impl_runtime_apis! {
 		fn on_chain_votes() -> Option<ScrapedOnChainVotes<Hash>> {
 			runtime_api_impl::on_chain_votes::<Runtime>()
 		}
+
+		fn candidate_included_state(session_index: SessionIndex, candidate_hash: CandidateHash) -> Option<BlockNumber> {
+			runtime_api_impl::candidate_included_state::<Runtime>(session_index, candidate_hash)
+		}
 	}
 
 	impl fg_primitives::GrandpaApi<Block> for Runtime {