Zebra crossings are for pedestrians only. If you are on your bike, you don’t count as a pedestrian, so you’ll need to dismount and cross. You can however cross on Toucan crossings, which are the button controlled traffic lights that allow pedestrians and cyclists to cross on the green signal.

Highway Code, Rules for Cyclists 79 Do not ride across a pelican, puffin or zebra crossing. Dismount and wheel your cycle across.