John Cleese has signalled he will vote to leave the EU - and suggested killing European Commission president Jean-Claude Juncker to help reform the bloc.

The outspoken comedian accused Mr Junker of "threatening" Britain and branded David Cameron's attempts at reform a failure as he plumped for an out vote on June 23.

READ MORE: 'Euro Trash': Brexit campaign savaged by biggest names in politics for dragging EU debate into gutter

Cleese said Britain had been "swimming against the tide" in its bid to bring about change in Brussels, where bureaucrats had taken away "any trace of democratic accountability".

The prominent Liberal Democrat supporter said it was a "sad" situation and appeared to address his message to party grandee Lord (Paddy) Ashdown, who is campaigning for Remain.

"If I thought there was any chance of major reform in the EU, I'd vote to stay in. But there isn't. Sad. Sorry, Paddy," he tweeted on Saturday.

READ MORE: 'Euro Trash': Brexit campaign savaged by biggest names in politics for dragging EU debate into gutter

Among the EU reforms suggested by the Monty Python star were "give up the Euro, introduce accountability,and hang Jean-Claude Juncker".

Cleese dismissed warnings by Remain campaigners that Britain's ability to trade would be damaged by a divorce from the EU, saying the country had done so for "millennia".

READ MORE: 'Euro Trash': Brexit campaign savaged by biggest names in politics for dragging EU debate into gutter

His pro-EU followers disagreed, with James Burns tweeting: "@JohnCleese Economically, we are better IN, according to the IMF, OECD, IFS, Bank of England, 90% of surveyed economies."

Luke Reid said: "@JohnCleese It would be terrible to vote for democracy and sovereignty!!!!"

Meanwhile BBC2 historian Greg Jenner tweeted: "John Cleese backs #brexit? This doesn't surprise me, I just hope lovely Michael Palin hasn't done the same. That will be a sad day."

READ MORE: 'Euro Trash': Brexit campaign savaged by biggest names in politics for dragging EU debate into gutter