Some Tory advocates of the move point to New York, where property taxes are much higher. But the fact that an idea originally floated by Labour is being discussed by the Government will infuriate many Tory activists.

The talks come as Treasury officials have privately compiled a lengthy menu of tax rises, including the proposed levy on expensive homes, capital gains, other stealth raids on business and even inheritance tax to pay for increased public spending while sticking to the Chancellor’s new fiscal rules.

One of the ideas being considered ­includes cutting pension tax relief for those earning £50,000 a year or above from 40 per cent to 20 per cent to raise an extra £10 billion a year, as the Financial Times reported yesterday. More than four million people, including many traditional Tory voters, would stand to lose out from such a policy.

Any move would be partly designed to send a signal to Northern and Midlands voters that the Tories were no longer the party of the Southern shires and middle classes, one source said. The Treasury’s desire to balance the current budget by 2023 was another reason cited.

Writing in The Sunday Telegraph, John O’Connell, chief executive of the TaxPayers’ Alliance, says: “It seems to be a misunderstanding of what the ­Tories’ new voters were looking for.

“They may be new converts to the message, but they still expect the ­Conservatives to be the ones backing them when they succeed. Levelling up doesn’t mean cutting other people down.”

A senior Conservative MP said he would be “stunned” if Mr Johnson and Mr Javid went ahead with either of the taxes, saying: “It is ridiculous. They need tax cuts, they need to ­promote growth.

“We have already got a mansion tax in excessive stamp duties and as a result the volume of transactions has halved and the revenues have come downThey should do the reform without the trade-off.

“They have got to get rid of this idea that people believe in the politics of jealousy. If you want to tax the rich out of the country you vote Labour or Liberal Democrat.

“If you are happy for people to get on in the world and make a good living you vote Conservative.”