BREXIT-BACKING tycoon Arron Banks faces a police probe over claims he broke campaign rules in the EU referendum.

The insurance magnate is accused of lying about the source of £8million of funding he gave the campaign group Leave.EU amidst claims it came from foreign donors.

Leave.EU, which was founded by Mr Banks and Nigel Farage, is also under investigation by the National Crime Agency, the UK's equivalent of the FBI.

The Ukip-supporting businessman calls himself and his allies the "Bad Boys of Brexit".

The Electoral Commission said today it was referring Mr Banks, Leave.EU and a company called Better for the Country which helped run the Brexit campaign to the NCA.

The elections watchdog said there were question marks over the source of £8million of the campaign group's funding - including £2.9million which was spent directly on the referendum.

There are "reasonable grounds to suspect" that Mr Banks did not provide the £8million of loans from his own funds, as he has claimed - while some of it may have come from illegal sources outside the UK.

The commission passed on the file to the NCA because it suspects that criminal offences may have taken place.

Mr Banks has previously faced questions over his links to Russia - he has repeatedly met with Vladimir Putin's ambassador and was offered a business deal over six goldmines in the country.

He has repeatedly denied any wrongdoing over the Brexit referendum, and insists all his fortune comes from his insurance businesses such as Go Skippy.

Mr Banks was once a Tory donor but switched his support to Ukip and became a close ally of Mr Farage.

He has recently encouraged Brexit voters to join the Conservatives in a bid to convince Theresa May to ditch her Chequers proposals.

Bob Posner of the Electoral Commission said today: "We have reasonable grounds to suspect money given to Better for the Country came from impermissible sources.

"This is significant because at least £2.9million of this money was used to fund referendum spending and donations during the regulated period of the EU referendum.

“Our investigation has unveiled evidence that suggests criminal offences have been committed which fall beyond the remit of the Commission.

"This is why we have handed our evidence to the NCA to allow them to investigate and take any appropriate law enforcement action."

The NCA said in a statement: "While electoral law offences would not routinely fall within the NCA’s remit, the nature of the necessary inquiries and the potential for offences to have been committed other than under electoral law lead us to consider an NCA investigation appropriate in this instance."

Mr Banks accused the Electoral Commission of carrying out a politically motivated witch hunt because of his support for Brexit.

He said today: "I am confident that a full and frank investigation will finally put an end to the ludicrous allegations levelled against me and my colleagues.

“There is no evidence of any wrongdoing from the companies I own. I am a UK taxpayer and I have never received any foreign donations. The Electoral Commission has produced no evidence to the contrary.

“I am already in court with the Electoral Commission. In witness statements the commission has admitted it got its figures wrong in relation to a previous investigation and it even submitted its final report without taking evidence from us. “

"Isn’t it funny that none of the financial contributions made by George Soros to British political campaigns are ever subject to any level of scrutiny by the Electoral Commission despite his being a foreign national."

He later took to Twitter to share a picture of himself with the caption, "Gone fishing!"