Brexit campaign was largely funded by five of UK's richest businessmen

The five contributed £15m out of a total £24.1m given to Leave campaigns in the five months before the referendum

The campaign to leave the European Union was mostly funded by five of the UK’s richest businessmen, a new study has revealed.

The five donors – including Leave.EU’s Arron Banks, Crystal Palace co-owner Jeremy Hosking, investment billionaire Peter Hargreaves, motoring entrepreneur Robert Edmiston and hedge fund manager Crispin Odey – contributed £14.9m out of the total £24.1m in donations and loans given to the leave campaigns in the five months leading up to the referendum.

According to analysis of the soon-to be published Sunday Times rich list, 71 per cent of funding for campaigns on both sides of the argument came from the UK’s richest people.

Mr Banks was the biggest anti-EU donor having given a £6m loan to Leave.EU, a group focusing on immigration controls that he helped found with Nigel Farage.

He gave a further £2.1m to Grassroots Out, a separate group, through his Better For The Country Ltd campaigning firm and was one of Ukip’s biggest individual donors until earlier this year.

Mr Hargreaves gave £3.2m to Leave.EU while Mr Hosking give £1.69m to Vote Leave.

Mr Odey donated £873,323 to get the UK out of the EU but was out of pocket for far more when his hedge fund lost half its value in six months after he predicted the decision would trigger a recession.

The largest donor to the Remain side was Lord Sainsbury of Turville, giving £4.23m to several pro-EU groups.

The revelation comes as the Electoral Commission announced it was investigating Leave.EU’s spending.

The commission said it was looking into whether the Brexit-supporting campaign had taken “impermissible” donations and that there were “reasonable grounds to suspect that potential offences” may have been committed by the campaign.

But Mr Banks rejected the allegations, saying: “The Electoral Commission allowed the Government to spend £11m on a pack of Remain lies. We will be vigorously defending ourselves against their allegations.”

Since the referendum Mr Banks has declared war on his former party and said he intended to stand against them in June in Clacton – the only seat they won in the 2015 general election.

In an interview with The Independent last month, he said he thought Ukip leader Paul Nuttall was “weak” and running the party “like a squash club”.

He said he wanted to run in Clacton to unseat the incumbent MP Douglas Carswell who later left the party to sit as an independent having previously defected from the Conservatives and triggered a by-election in 2014.

However, Mr Carswell announced last week that he would not be standing again in the general election on 8 June.