diff --git a/synapse/types/rest/client/__init__.py b/synapse/types/rest/client/__init__.py
index 489aa90809..21e18341ce 100644
--- a/synapse/types/rest/client/__init__.py
+++ b/synapse/types/rest/client/__init__.py
@@ -142,104 +142,6 @@ class MsisdnRequestTokenBody(ThreepidRequestTokenBody):
     phone_number: StrictStr
 
 
-class SlidingSyncStickyEventsToken:
-    """
-    A token returned by `next_batch` of the MSC4354 Sticky Events extension to Sliding Sync
-    and then accepted as the `since` parameter in the requests of the same extension.
-
-    Current format:
-        SlidingSyncStickyEventsToken ::= 'sticky_' UnresolvedMultiWriterStreamToken
-
-    where `MultiWriterStreamToken` is the serialised form of a (potentially sharded)
-    `MultiWriterStreamToken` for the sticky events stream, e.g. `42` or `m42~1.45`.
-
-    The `sticky_` prefix allows us to make sure it's not swapped for another token
-    or to evolve the type of token accepted with backwards compatibility in the future.
-
-    Note that the inner stream token can only be interpreted with access to the
-    database (to resolve instance IDs to instance names), so this class holds the
-    serialised form and converts on demand.
-    """
-
-    PATTERN = re.compile(r"^sticky_([0-9]+|m[0-9]+(~[0-9]+\.[0-9]+)*)$")
-    START: ClassVar["SlidingSyncStickyEventsToken"]
-
-    def __init__(
-        self, *, unresolved_stream_token: UnresolvedMultiWriterStreamToken
-    ) -> None:
-        self._unresolved_stream_token = unresolved_stream_token
-
-    @classmethod
-    async def from_stream_token(
-        cls, store: "DataStore", token: MultiWriterStreamToken
-    ) -> "SlidingSyncStickyEventsToken":
-        return cls(unresolved_stream_token=await token.to_unresolved(store))
-
-    async def to_stream_token(self, store: "DataStore") -> MultiWriterStreamToken:
-        return await MultiWriterStreamToken.from_unresolved(
-            store, self._unresolved_stream_token
-        )
-
-    @classmethod
-    def __get_pydantic_core_schema__(
-        cls, source_type: object, handler: GetCoreSchemaHandler
-    ) -> CoreSchema:
-        """
-        This function is checked for and used by Pydantic when
-        attempting to deserialise/validate a field of this type.
-
-        This returns a schema that will parse a string into an
-        instance of `SlidingSyncStickyEventsToken`.
-        """
-
-        return pydantic_core.core_schema.no_info_plain_validator_function(
-            cls._validate,
-            serialization=pydantic_core.core_schema.plain_serializer_function_ser_schema(
-                cls.serialise,
-                info_arg=False,
-            ),
-        )
-
-    @classmethod
-    def _validate(cls, v: object) -> Self:
-        """
-        Create an instance from serialised string form.
-
-        The inverse of `serialise`.
-        """
-        if isinstance(v, cls):
-            return v
-        if isinstance(v, str):
-            match = cls.PATTERN.match(v)
-            if match is None:
-                raise ValueError(f"Invalid SlidingSyncStickyEventsToken format: {v!r}")
-
-            return cls(
-                unresolved_stream_token=UnresolvedMultiWriterStreamToken.parse(
-                    match.group(1)
-                )
-            )
-        raise ValueError(f"Cannot parse SlidingSyncStickyEventsToken from {type(v)}")
-
-    def serialise(self) -> str:
-        """
-        Convert this instance to string.
-
-        The inverse of `_validate`.
-        """
-        return f"sticky_{self._unresolved_stream_token.to_string()}"
-
-    def __repr__(self) -> str:
-        # Use the serialised form as debug output.
-        return self.serialise()
-
-
-# Starting reading a stream at 0 ensures all stream fact rows will be read
-SlidingSyncStickyEventsToken.START = SlidingSyncStickyEventsToken(
-    unresolved_stream_token=UnresolvedMultiWriterStreamToken(stream=0)
-)
-
-
 class SlidingSyncBody(RequestBodyModel):
     """
     Sliding Sync API request body.