Senior figures at Transport for London (TfL) believe Boris Johnson is trying to rush through his plans for segregated cycle lanes in London too quickly, Politics.co.uk can reveal.
The London mayor has promised to build a series of segregated cycle routes across London over ten years.
The plans are broadly supported by cyclists but are meeting stiff opposition from motoring and business groups, who believe the lanes will cause congestion.
A senior source at TfL told Politics.co.uk that they were concerned that the mayor's cycling ambassador Andrew Gilligan had not effectively explained the policy to Londoners.
"It's not a bad policy as long as you communicate to people what it entails and I'm not sure that's been done," they said.
The source described Mr Gilligan as a "zealot" and suggested that he had failed to convince anyone beyond those already persuaded by the need for the new segregated cycle lanes.
They pointed to new figures showing the mayor's cycle superhighways will delay other journeys across London by up to 16 minutes on some routes.
"There will be people whose journeys will take longer as a result of this" they said, adding that they expected taxi drivers to be heavily opposed.
They said that they were particularly worried about the impact of the new east-west cycle superhighway on pedestrians.
TfL this month released figures showing that pedestrians will have to wait up to nine seconds longer to use some crossings on the route.
The source said the new lanes would take longer than expected to implement and suggested that the mayor's ten year budget for the programme could be scaled back in future years.
"He [Gilligan] is fixated on the £913 million figure, but I'm not sure how many years it is going to take to spend that," they added.
They also suggested that the mayor himself was not as convinced by the need for segregated cycle routes as his adviser.
The comments suggest that TfL have some sympathy with business and motoring groups who have launched a fightback against the mayor's plans in recent weeks.
The City of London corporation has said the plans are being pushed through in a "tremendous rush" while the RAC foundation and others believe the lanes will increase congestion.
This opposition has coincided with news this week that two of the mayor's planned 'cycle superhighways' have been axed by TfL, while a third has been delayed until 2017.
One source close to the mayor told Politics.co.uk that Transport for London had been a roadblock to the mayor's cycling plans in the past.
They said the body had tried and failed to reduce London's cycling budget at the time of the government's comprehensive spending review last year.
However, City Hall today insisted that the mayor's cycling vision would go ahead as planned.
They also insisted that the average delays to other road users caused by the new lanes would be minimal.
"I'm not aware of any proposal to slow down spending on cycling," Andrew Gilligan told Politics.co.uk.
He said that City Hall were working hard to explain the policy.
"I completely agree that we need to be as open as possible about the consequences of these plans," he added.
"We have always been honest that there will be some impacts on motorists and that we're prepared to consult and make changes where necessary."
Johnson's opponents today warned that any progress the mayor has made on cycling could be lost when he leaves office.
"Boris Johnson has been Mayor for six years but we are only now getting serious action to make junctions safer," Green Party London Assembly member Darren Johnson said.
"Unless Boris gets things done by 2016, then the bulk of his cycle schemes could be dumped by the next Mayor.
"Transport for London did this in 2008, when they persuaded Boris Johnson to withdraw planned funding for a 900km Pan London network of cycle lanes which the previous administration had pushed through.”