Cycle Lanes are marked with a white line (which may be broken) along the carriageway.
You should keep within the lane when practicable.
Use of cycle lanes is not compulsory. The common belief is that cyclists are advised to use cycle lanes but this is also not strictly true. Rule 63 of the Highway Code describes cycle lanes, but does not say that cyclists should use them, merely that use of them "depends on your experience and skills, but they can make your journey safer".
Most cyclists will choose to use good quality cycle lanes where they exist, but where they are badly designed, littered with glass or badly maintained, they won't. You are entitled to make you own choice, and the Highway Code rule merely reflects that.
Cycle Tracks are a route other than within a carriageway used by a bike, for example, a footway adjacent to a carriageway but separate from the carriageway itself.
Cycle Paths are a grey phrase, which can mean a variety of things. It could be interpreted as a bridleway of ‘shared usage’ or exclusively a ‘bike path’. It is unclear exactly what constitutes a “Cycle Path”.
Many cycle lanes can now be found on footways with signage and stating the route is for ‘shared use’. Cyclists must not assume this means they have right of way on the cycle ‘half’ of the shared-use facility. You should always respect pedestrians even if they stray onto the cycling side (if there is one); they are entitled to do so.