Boris Johnson has written to Jeremy Corbyn accusing him of a “sly” plan to “fiddle” a second Brexit referendum, which he said was "profoundly undemocratic."
The prime minister has urged the Labour leader to reconsider his Brexit policy and his plan to give full voting rights to all UK residents, with Mr Johnson saying it would give two million EU nationals the vote in another referendum.
Mr Johnson said Mr Corbyn’s approach has “already done serious harm to trust” in politics, adding that cancelling the result of the 2016 referendum before it has been implemented would do more damage.
Labour has said it will “give the people the final say” on Brexit, and within three months of coming to power a Labour government would secure a “sensible deal”, and within six months they will put that deal to a public vote alongside the option to remain.
In his letter to Mr Corbyn, the prime minister wrote: “Your policy is to cancel the result of the last referendum and to hold another one.
“You have made clear that you oppose an Australian-style points system and you will not only continue ‘free movement’ with the EU but your policy is extend it to the entire world.
“Even worse, your manifesto sets out plans to fiddle your second referendum on Brexit. You want to give two million EU nationals the vote in your referendum.
“This is a sly attempt to undermine the result of the 2016 referendum, and is profoundly undemocratic.
“No true democrat, even the most ardent supporter of Remain, could support your attempt to undermine the result of a democratically expressed vote.
Mr Johnson urged the Labour leader in the "strongest possible terms" to reconsider his Brexit policy before the election on Thursday.
“Your approach has already done serious harm to trust in democratic politics and cancelling the result of the previous referendum before it has even been implemented will do more damage," the prime minister said.
“But your policy of giving millions of foreign citizens the vote in order to overturn the referendum would create incredible bitterness that might take decades to repair.
“Imagine how people will feel if the biggest democratic exercise in our history is overturned because you gave two million EU citizens the power to reverse Brexit.
“It would alienate millions who already feel disenfranchised and ignored by our political system.”
Mr Johnson said “very few” voters are aware of this policy, and he fears that if Mr Corbyn becomes Prime Minister it will “create the worst crisis in democratic politics in over a century”.
On Thursday afternoon, Mr Johnson was asked a question on whether EU citizens should be able to vote in a possible future Brexit referendum, and he said: “I think the whole proposal from the Labour Party is bizarre.
“I think people will be outraged by the whole thing and… to think that it is going to be rigged in some way by getting in millions more voters who’d be very likely to vote one way rather than another, I think that would cause a great deal of public disquiet and I don’t think it’s the right way forward.”
Cat Smith, Labour’s shadow minister for voter engagement, said: “The Labour Party believes in democracy. We welcome securing a new and better Brexit deal, and putting it back to the people to have the final say.
“If Boris Johnson had any confidence in his own deal, he would have let it be scrutinised by Parliament, and then put it back before the people for their verdict.”