BREXIT’S big money backer Arron Banks is being investigated by the elections watchdog over claims he may have broken finance rules in the run up to the 2016 EU referendum.

The Electoral Commission is to probe the millionaire-diamond mine owner’s charity Better for the Country Limited (BFTCL), which, though not registered as a permitted participant in the referendum, made donations totalling £2.3m to five other campaigning organisation. It follows on from investigations by the Open Democracy website into so-called “dark money” spending made during the referendum.

The commission will look at whether BFTCL was the true source of donations made to referendum campaigners in its name, or if it was acting as an “agent” for another person or group or even another country.

Loans from Banks to Leave.EU totalling £6m will also be probed by the Commission, as they, again seek to see if he was the true source of loans reported or if he was acting as an “agent” for someone else.

Bob Posner, the commission’s director of political finance and regulation, and legal counsel, said: “Interest in the funding of the EU referendum campaigns remains widespread.

“Questions over the legitimacy of funding provided to campaigners at the referendum risks causing harm to voters’ confidence.

“It is therefore in the public interest that the Electoral Commission seeks to ascertain whether or not impermissible donations were given to referendum campaigners and if any other related offences have taken place.”

Among the recipients of donations from BFTCL was the Grassroots Out campaign which was supported by some Tory MPs, including Brexit Secretary David Davis.

Donations, made between March and June 2016, were also made to Trade Unionists Against the EU; Veterans for Britain; WAGTV Limited; and Ukip, led at the time by Nigel Farage.

Labour MP Ben Bradshaw raised the question in Parliament during Prime Minister’s Question time yesterday, and suggested there could be a link between Banks and the Russian government.

Banks was dismissive of the probe and the allegations of Russian interference in the referendum, describing it as “complete bollocks from beginning to end.”

In a statement, Banks said: “My sole involvement with ‘the Russians’ was a boozy six hour lunch with the Ambassador where we drank the place dry (they have some cracking vodka and brandy!) and then wrote the account of the lunch in my book.

“Ben Bradshaw, working with Open Democracy created a work of fiction. He asked a question in Parliament and today got the Electoral Commission to leak the news of the inquiry and then hit the airwaves. Yawn…”

He added that the probe was the “Remain establishment once again trying to discredit the result” of the EU referendum.

Banks previously claimed he is worth £100m, other reports put it closer to £250m though, analysis by Open Democracy suggests the actual figure is considerably lower.