London’s 15-mile East-West Cycle Superhighway – a pillar of city mayor Boris Johnson’s Vision for Cycling – could be under threat as the government prepare to cut spending.

According to reports in the Evening Standard, part of the £913m the mayor planned to spend to double the number of journeys made by bike and make cycling safer is considered a “vulnerable” project at the Treasury for the next comprehensive spending review, scheduled for 26 June.

Chancellor George Osborne has final approval of more than £600m of the budget the mayor has allocated to cycling, the paper reported.

Johnson unveiled his Vision for Cycling in March, outlining a “Crossrail for bikes”, a network of routes through quiet streets, a grid of partially segregated routes across the city centre and action on lorry danger and measures to improve lethal junctions.