You are allowed to have flashing bike lights, the law has changed.
http://www.direct.gov.uk/en/TravelAndTransport/Highwaycode/DG_069837
@AlexB started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
You are allowed to have flashing bike lights, the law has changed.
http://www.direct.gov.uk/en/TravelAndTransport/Highwaycode/DG_069837