Britons could be persuaded to turn away from Brexit if there is a "game-changer" shift in policy from Brussels on issues including immigration, Gordon Brown has suggested.

The former prime minister predicted there would be a "crisis point" next summer as Leave voters realise the promises made during the referendum campaign will not be kept.

Mr Brown suggested that if Brussels put additional restrictions on the freedom of movement it could swing people from Leave to Remain if it was put to another vote.

"By next summer, the public will have made up their mind that the four red lines that the Government had actually set in place are not going to be achieved, they're going to be crossed," he told the BBC.

"So we will not have proper control of borders. We will not have proper control of our money. We're still going to pay loads of money to the European Union.

"We'll not have proper control of our courts, the law, because we'll still be governed in many ways by the European Court of Justice.

"And we'll not have proper control of trade because we won't have individual trade agreements for years.

"And so all the propositions that were made by the Leave camp, including £350 million, remember, a week for the National Health Service, they're not being achieved."

Mr Brown said: "You cannot go back to the electorate and say 'you were wrong'."

But he added: "What you can say, is there a game-changer?

"Is there something that we didn't get right the last time that would persuade millions of Leave voters to think it was worth going for Remain?

"And that game-changer must have the support of course of the rest of Europe because we couldn't get it through otherwise and I would like to see a situation at the end of negotiations where we say that's what you get when you leave but is there something else that is a game-changer that you get if you're prepared to stay?"

That would mean having something to say "about migration, about the courts, about money".

He said other EU countries were seeking reforms to free movement rules.

"Belgium has been engaged in new agreements about freedom of movement.

"France is talking about the social dumping as they call it of workers in France.

"There's a lot that is happening in the European Union that might, if it had been known, have changed the position."