TfL is using new enforcement powers 

Transport for London (TfL) has been given expanded enforcement powers and has begun fining motor vehicles caught driving in mandatory cycle lanes and cycle tracks.

TfL will issue fines to vehicles that drive within, or cross, the white lines of cycle lanes that are marked by a solid white line and cycle tracks. 

The Government has introduced new powers allowing TfL and London boroughs to fine motorists who infringe on cycle lanes and cycle tracks in the same way that they currently do for bus lanes and yellow box junctions. These powers were introduced at the same time as wider national changes giving local authorities in England outside of London the powers to enforce moving traffic contraventions

Initially, TfL will use existing CCTV cameras to enforce contraventions in cycle lanes and cycle tracks at key locations across its road network. 

See information on the BVRLA website: Statutory guidance for moving traffic offences published