David Cameron has said he would not support Turkey joining the European Union in the next couple of years, but said it was "completely untrue" for the Vote Leave campaign to claim the issue would even arise.
With just three days to go until the public vote in the referendum, the prime minister said it would be "crazy" for the UK to choose Brexit on the basis of possible Turkish EU membership.
"If this was going to happen in next couple of years I would not support it, but it’s not going to," he told a special referendum edition of BBC Question Time on Sunday evening.
However Cameron dodged questions over whether he would veto Turkish membership if it was proposed further down the line.
"I think this is the biggest red herring in this whole referendum debate," he said. "I can’t find a single expert anywhere where the country or in Europe that thinks Turkey is going to going to join the EU in the next three decades."
The Vote Leave campaign, led by Michael Gove and Boris Johnson has produced posters claiming "Turkey is joining the EU".
The justice secretary and former London mayor have demanded Cameron commit to vetoing Turkish membership in order to prevent its citizens being granted the same freedom of movement rights as other current EU members enjoy.
Cameron told the BBC Question Time audience that if the UK voted to leave the EU on Thursday "let's not do it on three things that are completely untrue".
"People are getting through their letterboxes, leaflets from Leave, saying basically Turkey is going to join the EU, not true. There is going to be an EU army with Britain in it, not true. And we give £350m a week to Brussels, not true," he said.
The prime minister said to vote for Brexit "on a basis of something that is not going to happen" would be "a crazy thing to do".
"I don’t want anyone to vote in the referendum on the basis of Turkey joining because it’s not going to happen." he said.
Following Cameron's TV appearence, Tory defence secretary Penny Mordaunt said Cameron was wrong to say the UK could veto Turkey joining the EU.
Her claim was immediately criticised by MPs supporting the Remain campaign.
"Penny you are wrong. You are asserting a completely false position. Why not tell the truth?" Labour's Jo Stevens tweeted at the minister.
Conservative Gavin Barwell said what Mordaunt said was "not true". He told her on Twitter. "Sure you wouldn't want to mislead people so please correct."
The prime minister also attacked Nigel Farage for producing a poster that showed a line of refugees. "I think that poster was irresponsible I think it is an attempt to frighten people," he said.
Earlier today, Gove said the poster made him "shudder". And George Osborne said it was "vile" and compared to to Nazi propaganda.