Angela Rippon, Len Goodman and Gogglebox's June Bernicoff have also put their names to the letter.

The stars said they were "deeply worried about the poorest older people who are set to lose out".

Their message comes as MPs prepare to question BBC executives about the subject at the House of Commons.

Director general Tony Hall and chairman Sir David Clementi are among those who will appear in front of the culture select committee from 14:30 BST.

Last month, the BBC decided it would only provide free TV licences to over-75s who receive the pension credit benefit.

The corporation said it could not afford to waive licence fees for all over-75s after the government passed responsibility for the provision to the broadcaster.

The open letter, also signed by Christopher Biggins, Lionel Blair, Ricky Tomlinson, Ben Fogle, Ed Balls, Miriam Margolyes and Lesley Joseph, will be taken to Conservative Party headquarters later by the Age UK charity along with more than 30,000 letters from members of the public.

The celebrities' letter said: "We collectively urge the next prime minister, whoever that may be, to save free TV licences for the over-75s.

"We're extremely disappointed that free TV licences are being taken away from the vast majority of over-75s and are deeply worried about the poorest older people who are set to lose out because they don't claim pension credit - a benefit which is massively under-claimed by this age group."

Television provides "a great source of companionship" for those who live alone, have lost a loved one or have health and mobility issues, they said. "It helps them connect to the outside world and brings news and entertainment to lonely and dark days."

Responsibility for paying for free TV licences for the over-75s should "never have been handed over to the BBC in the first place", the letter added.

"It is the government's place to fund free TV licences and we call on the government to think again and do what's right for the oldest in our society. TV is their lifeline - their friend. Please don't take it away from them."

Dame Helen told Age UK it was "heartbreaking" that so many people could lose "an important contact with the outside world".

A government statement said it was "very disappointed" with the BBC's decision.

"We've been clear that we want and expect the BBC to continue this concession," it said. "People across the country value television as a way to stay connected, and we want the BBC to look at further ways to support older people.

"Taxpayers want to see the BBC using its substantial licence fee income in an appropriate way to ensure it delivers for UK audiences, which includes showing restraint on salaries for senior staff."

Boris Johnson, the frontrunner to be the next prime minister, has reportedly said the BBC "should be coughing up for the TV licence for the over-75s", suggesting it could "sack Lineker" to pay for them. Match of the Day host Gary Lineker is the corporation's best-paid presenter, on £1.75m a year.

The corporation has said keeping free licences for all over-75s would cost £745m, a fifth of the BBC's annual budget, by 2021/22.

Mr Johnson's rival for the premiership, Jeremy Hunt, has reportedly said the provision should be protected.