LONDON (Reuters) - Brexit could be reversed if economic pain prompts a change in public opinion that brings a new generation of political leaders to power in Britain, former Conservative minister Michael Heseltine said.

Heseltine, who helped topple Margaret Thatcher in 1990 but ultimately failed to win the top job, said that Britain could face another election in just two years and that Prime Minister Theresa May would not lead the party into that election.

A supporter of EU membership, Heseltine said he saw a scenario in which Britain would not leave the European Union as scheduled in late March 2019.

“There is now a possibility that Brexit will not happen, but it will need a change in public opinion,” Heseltine, 84, told Reuters in an interview.

“There may be indications but there is no really substantive evidence of public opinion moving but I think that it will happen. My guess is that public opinion will move,” he said.

Heseltine said the shift in Brexit policy by the opposition Labour Party - including staying in the European single market and customs union for a transitional period - indicated Labour had sensed the wind of a change in public opinion.

May, who quietly opposed Brexit ahead of the referendum, has formally notified the bloc of Britain’s intention to leave and divorce talks are under way.

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Some European leaders have suggested Britain could change its mind, while former Conservative prime minister John Major has said there is a credible case for giving Britons a second vote on the Brexit deal.

His successor, Labour’s Tony Blair, has said repeatedly that Brexit can and should be stopped.

In the June 2016 referendum voters in the United Kingdom backed leaving the EU by a margin of 51.9 percent to 48.1 percent.

The world’s fifth-biggest economy initially withstood the shock of the Brexit vote, but growth began to slow sharply this year as inflation rose on the falling value of the pound and hit households.

CHANGE THE BREXIT TUNE

May, who has insisted that Britain will leave the European Union, said last month that she wanted to fight the next parliamentary election, not due until 2022.

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Heseltine, though, said that seemed unlikely given her botched gamble on a snap election in June which lost her party its majority in the lower house of parliament.

“I don’t think she will fight the next election, but there is no agreement on her successor. All the people indicated as possibles are singing the same song, and in my view the song is unattractive and will become less attractive,” he said.

“‘Ousted’ is a specific word, but there are many ways in which the Tory party operates - what it will quite look like I am not going to say. But I think there will be a change to a new leader before the next election.”

“They have two years before the next election.”

Heseltine said he was waiting for a politician to emerge with the courage to challenge the Brexit consensus of British politics and explain to voters the full import of the divorce.

“Within a relatively short period of time, the Brexit negotiations will sour even more than they already have, and the Tories will be left holding the baby. Everybody else will have moved away from Brexit,” Heseltine said.

Brexit, he said, was a “monumental mistake” that would make Britain a spectator of 21st century history, bleed its wealth and relegate it from the league of leading global powers.

“The idea that we are not European is just to spit in the wind: Anyone who has read Shakespeare knows just how European we are,” said Heseltine, who the Sunday Times says has a fortune of 300 million pounds ($390 million).

He said Brexit was far more significant than the 1956 Suez crisis, when British forces were forced by the United States to withdraw troops from Egypt in a blunt illustration of Britain’s lost imperial power.

Heseltine said the EU was unlikely to give Britain the beneficial divorce deal it wanted because to do so would risk unraveling the EU itself.

“It is difficult to see how the Brexit negotiations can be anything other than discordant. The issues are huge and they come down to a very simple question: Can the Europeans agree to someone leaving the club on ‘the cake and eat it’ basis?”

“I don’t think they can. And they have made it clear they don’t intend to. If they were to change their mind so that we have our cake and eat it, well of course I will be wrong. But I don’t think they are going to do that.”