Tony Blair has suggested that the UK could stay a member of the European Union because the public might change its mind over Brexit.

The former Labour prime minister said that voters could still balk at the "severe consequences" of leaving the EU.

These would become clear only after formal negotiations with Brussels begin, he suggested.

More than four million people signed a petition calling for the UK to remain in the EU in the wake of the shock referendum result.

But Prime Minister Theresa May has insisted that ‘Brexit means Brexit’.

She has also said that curbs on EU migration will be one of her ‘red lines’ during exit talks.

Her comments effectively rule out a Norwegian- style option, in which freedom of movement is retained in return for access to the Single Market.

The Scottish Government has warned that the free movement of people across Europe is crucial to Scotland’s attempts to grow its population.

Despite Mrs May’s stance on migration, Mr Blair told a French radio station that there was no clarity over what Brexit actually meant.

He told Europe 1: “You must accept we’ve had the referendum, we’ve had the debate but at the moment the debate continues because... we haven’t seen what ‘Brexit’ means.".

"What does that mean for the Single Market, for carmakers, for financial markets, for the free movement of people?”

He added: “The pound is collapsing, we have lost, I think, 15 per cent and that is something real. We can see the costs but also there will be problems with investments in the UK.

"It’s not absolutely clear at the moment but there will be a moment where we will have a negotiation; we will see the terms the rest of Europe are offering.

"We can see ‘it’s a good idea’, we might also see it’s a bad idea with severe consequences."

He claimed that the UK could still decide not to leave the EU, although he admitted that that was unlikely.

“We can say at the moment it’s not probable, today. But the debate, as I’ve just said, continues and I think that it’s possible, yes.

"Who has made a rule that we must end the debate now?"

Asked if the British people might change their minds about Brexit, he added: “Yes, we have the right.”

As well as limits on migration Conservative misters have said that they want the best deal for British firms.

But critics claim that for many industries those two aims are incompatible.

Farmers’ leaders have warned that fruit farms and abattoirs will be severely hit by a loss of EU labour.

Just hours before Mr Blair’s comments the deputy prime minister of Poland Mateusz Morawiecki suggested that hundreds of thousands of his countrymen and women could leave the UKover the next few years.

On a visit to the Midlands, Mrs May said that the UK was still open for business.

“This country has always been one of the greatest trading nations, and as we leave the European Union we will have the opportunity to embrace new markets and opportunities as we export British innovation and expertise to the world," the Conservative leader said.

"I am determined to make the most of the opportunities Brexit presents – delivering the change that people want and striking the right deal for British businesses at home and abroad.”

Brexit Secretary David Davis said: "It is extraordinary, if depressingly predictable, that Tony Blair now tries to claim that there is no need to accept the result of the referendum supported by his party, which delivered a bigger popular vote for leaving the EU than that won by any government in history.

"Mr Blair demonstrates how out of touch he is with the country - and indeed with many of those individuals and organisations who supported Remain, but have accepted that people have spoken loud and clear and are engaged in identifying and preparing to seize the many opportunities that will flow from Brexit."