A £64m shortfall in Transport for London's (TfL) budget means scores of transport schemes will have to be delayed or shelved.
Public transport is a victim of the congestion charge's success
London's transport body said the cash problem was caused by lower than expected revenues from the congestion charge.
TfL said the scheme's success at reducing traffic levels by about 20% has meant fewer drivers than expected are paying the £5-a-day charge.
But Conservatives on the London Assembly are outraged that £31m from the budget is being used to give to Capita, the private company which administers the charge.
Without that money Capita would have made zero profit from the scheme - the Tories say that possibility should have been foreseen.
Cars have kept away from the congestion charge zone in central London since the road toll was introduced on 17 February.
Widening of the North Circular shelved
Plans for three-car trains on the Docklands Light Railway deferred for two years
Road improvements and maintenance deferred
TfL had expected to receive £130m a year from the congestion charge scheme - out of a total transport budget of more than £1.2bn.
Conservative London Assembly member Angie Bray said: "Capita appear to get all of the rewards whilst Londoners have to pick up the costs.
"This illustrates the inherent contradiction at the heart of the scheme - the desire to raise revenue against a desire to cut congestion.
"The fewer cars that enter central London means less money raised for public transport improvements."
Meanwhile BBC London has learned that some of the congestion charge cameras are not working properly.
Some are being blinded by the glare of the sun reflecting off number plates - making them either fuzzy or unreadable.
An emergency programme is under way to fit polarizing filters to cut out the glare.
TfL said the £31m going to Capita was part of a renegotiated contract with the firm and would mean improvements in the way the scheme worked.
"The £31m we anticipate will be completely recovered by increased revenue both by penalty charge notices and by compliance with the scheme," TfL's Peter Hendy told BBC London.