Opponents of parking charges in Bushy and Richmond Park have attacked councillors for not doing enough to help their campaign.

A letter leaked to the Richmond and Twickenham Times from the council’s cabinet member for traffic, transport and parking, Councillor David Trigg, showed he had written to Royal Parks (RP) – which manages both parks – in February asking them to consider linking parking fees to CO2 emissions.

In the letter, Coun Trigg asked RPA to do parking impact assessments and traffic studies but also mentioned the council’s parking permit scheme – where residents pay more to park in controlled parking zones if they have higher emitting vehicles and less if their cars produce less carbon.

He wrote: “If charges are to be introduced then we would encourage the Royal Parks, as an environmentally conscious organisation, to adopt a similar approach and base their charges on the emission of the vehicle.”

Annie Murray, from the Keep Bushy Park Free Alliance, said the council had told her it was against the charges, but she had seen them doing very little in opposition.

“We have had conversations with the council and they have said they are definitely on our side, and very concerned about congestion.

“But they have been very quiet. I have not noticed them being vocal at all.

“I didn’t notice any of them on our protest march, but Vincent Cable was there.”

Pieter Morpurgo, chairman of the Friends of Bushy and Home Parks, said: “We want to keep the park free for all.

“Of course we are very concerned about the environment but I think charging with CO2 would be irrelevant in the park.

“There are a lot of cars and it would be no better if they drive around the outside of the park looking for somewhere to stop than if they park in a car park.

“The important thing is to keep the pressure on to change these proposals.”

Richmond Conservatives accused Coun Trigg of failing to stand up for residents and Councillor Pamela Fleming, the business spokesman, said it was “deplorable” for him to offer to help the parks bring in variable charges.

Councillor Nick True, leader of Richmond Conservatives, said: “Instead of speaking for people and rejecting these charges, this ideologically obsessed anti-car council is offering to help design them.

“This is an arrogant council that does not listen and has forgotten how to represent people.”

Twickenham MP Vince Cable and Tony Arbour, Richmond Conservative London Assembly member, have echoed calls from Kingston and Wandsworth councils – which called the charges unfair and unwelcome – for the scheme to be scrapped.

Coun Trigg said: “Royal Parks is autonomous and can do whatever it wants.

“We wrote to them and said we wanted them to introduce more bus services and encourage cycling, but if they are to press ahead with parking charges we would like them to follow our example.

“My view is that they should not introduce charges and should make sure there is better public transport.

“I have made it clear the residents affected by this are not happy and do not want this.”

Mr Cable joined members of the Keep Bushy Park Free Alliance – comprising the Friends of Bushy and Home Parks, Hampton Hill Association, Hampton Society, Hampton Wick Association and the Teddington Society – at the Royal Parks offices in Hyde Park on Wednesday to hand in a 6,133-signature petition opposing the introduction of car parking charges in Bushy Park.

RPA’s consultation is due to end tomorrow.