A million-pound project to make Hampstead Heath station accessible has been branded a “farce” after it emerged new lifts will not be accompanied by ramps to trains.

Transport for London (TfL) is facing fierce criticism this week after admitting that the scheme will not include permanent ramps to take wheelchair users between trains and platforms.

The news has outraged campaigners who battled for years to make the Overground station accessible, largely because it serves the Royal Free hospital in Pond Street, as well as the Park End Surgery in Park End.

Jonathan Bergman, who spearheaded the Uplift for Hampstead campaign, said: “I have been contacted by wheelchair users who say this is ridiculous. Without the ramp, what’s the point?”

Jan Williams, secretary of the patients’ group New End Surgery, said: “They’re spending thousands of pounds on this lift but it’s ludicrous that there’s not going to be a ramp.”

In an email to councillors, Dr Marek Koperski, a Camden GP who teaches at the Royal Free, wrote: “As far as I understand, one to the main purposes of installing lifts is to help disabled patients attending the Royal Free Hospital (and elsewhere). The lack of a ramp means that the station would not be wheelchair friendly, which seems to defeat the purpose.”

Having first tabled the idea in 2002, the Uplift for Hampstead campaign secured a famous victory in 2011 when the Department for Transport announced its intention to allocate £1million. Hundreds of residents, including comedian Sue Perkins and jazz musician John Etheridge, had given their backing.

It was only after work finally started a few weeks ago that the lack of ramping came to light. TfL says the modifications cannot be made because the line is used by freight trains with different dimensions to the passenger stock. Wheelchair users have been told they will have to use a portable ramp and advised to phone 24 hours ahead so station staff can be booked to assist.

In an email to campaigners, TfL’s stakeholder communications manager Gary Nolan said: “It is preferable to arrange customer assistance in advance, as that will ensure a member of staff is there to meet you.”

But campaigners insist there must be a solution. Tom Brent, an environmental designer of South Hill Park, said: “It’s a farce. It’s complete lunacy for this to arise only now.

“I’m a designer and I understand how things work, and I know there must be an answer for this.”

Hampstead Town Cllr Chris Knight has written to the Mayor of London this week calling for an investigation, while his ward colleague Cllr Linda Chung said it was “discriminatory” to ask disabled people to call ahead and that the lift risks becoming a costly “white elephant”.

However, Casimir Knight, 46, of South Hill Park, said the lifts alone will be a huge boon to his 15-year-old son Ben, who uses a wheelchair: “For people in big mechanical chairs, it could be a problem, but for those in smaller chairs, who are going out with a friend or family member, it’s not a big problem.

“For us the project is wonderful and from our particular family perspective, it’s 90 per cent of the problem solved.”