Twickenham’s MP is facing a backlash from members of his own party – and borough homeowners – over his “mansion tax” proposals.

Hundreds of Richmond residents would face yearly bills totalling thousands of pounds if Vince Cable’s plan to charge council taxpayers at 0.5 per cent of a property’s value over £1m became a reality.

There are more than 300 houses for sale in Richmond that would be eligible for the “supertax” – but that figure would soar taking into account homes not on the market.

However, Dr Cable, the Liberal Democrat treasury spokesman, told the RTT only a small number of homeowners in the area would be affected and, of those, “people very well off would see the merits”.

His constituents in Montpelier Row, a small road in Twickenham lined with expensive homes, feel differently.

Homeowner Jill Jones, who paid less than £50,000 for her property when she moved in 41 years ago, said: “It’s ridiculous.

“I must say he’s making life for himself a bit difficult. Even his own party has been shocked by this.

“Does he expect me to move out of my house after 41 years?

“He is liked, he is a nice man but I think he may live to regret it.”

Neighbour Joyce Findlay said: “It’s nonsense, I was going to vote for Vince Cable but I’m not anymore.

“The houses in this neck of the woods are all hard earned – we are not mansion-type people.”

Fellow Lib Dems Susan Kramer MP and Richmond Council’s leader, Councillor Serge Lourie, were both quick to distance themselves from Dr Cable’s comments, made at the party’s conference in Bournemouth on Monday, insisting it was not party policy.

Coun Lourie said Dr Cable’s ideas were generally “very good” and added: “On this one he’s got it completely wrong.

“My view is that it would be very damaging to residents in Richmond who are often capital rich and revenue poor. I will be arguing strongly against it.”

Ms Kramer said: “I am very concerned there are ordinary families with modest incomes who will be penalised because house prices have risen to such high levels here.”

Her Conservative rival, Zac Goldsmith, added: “It would hit a lot of Richmond residents, and it doesn’t seem to have taken into account the many fixed-income pensioners who would be forced to leave their homes.”

But Dr Cable, the party’s deputy leader, insisted that critics “have got the wrong end of the stick”.

“I think in terms of the borough it’s overwhelmingly favourable,” he said. “The key point is we are talking about different ways of raising money in order to cut taxes.

“There will be tens of thousands of residents who are on average incomes and pensions who will benefit from tax cuts.”

However, he conceded: “It may be that we could have explained in more detail how in a practical way it would work to help most people.”

The aim would be to raise billions for a rise in the starting rate of tax to £10,000 by introducing the household levy on homeowners such as multi-millionaires Roman Abram-ovich and Lakshmi Mittal.