Property deals are falling through and wealthy foreigners are looking to sell up in central London following Ed Miliband’s announcement on taxing non-doms if Labour win the election.

Rich foreigners are also nervous of the possibility of a Mansion Tax, as some opinion polls show Labour ahead of the Tories.

Ed Mead, of Douglas & Gordon, said his firm has carried out 37 valuations in the last month for owners of high-end homes, against the normal six.

Another agent, Charles McDowell, said he has had two fall-throughs in the week since the non-dom announcements.

Mead said: “It is like the 1970s again, when waves of wealthy people left Britain and it was a disaster.”

Miliband’s announcement – that people who have made their homes in the UK should be made to pay full UK taxes – was designed to be a vote-winner but critics say it would lose more money than it would gain.

Under Labour’s plans, genuine temporary residents from abroad would probably still have non-dom status for three to five years, with the time limit to be consulted on.