LONDON, Aug 24 — A British businessman who helped bankroll the Brexit campaign has failed in his bid to join Britain’s governing Conservatives to try to ensure the party’s next leader is a hardliner.

Arron Banks, founder of the Leave.EU campaign, believes the battle for how exactly Britain will exit the European Union is now an internal struggle within the Conservative Party.

He has been encouraging fellow hardcore Brexiteers to join the centre-right party and help get in a new leader — and therefore prime minister — if Theresa May is ousted.

New members would be able to vote in the Conservatives’ next leadership election whenever it comes.

According to British media, May could face a challenge from Brexiteer Boris Johnson, the former foreign secretary who resigned last month over her Brexit policy.

London and Brussels have yet to reach an agreement on the terms of Britain’s exit from the bloc, and Conservative lawmakers are split on May’s proposals to keep Britain close to the EU on trade — parts of which have since been rejected by Brussels.

Banks, mainly involved in the insurance business, yesterday voiced his objection to May’s Brexit blueprint, struck with her cabinet at the PM’s Chequers country residence.

"The Conservative grassroots can challenge the leadership and the conditions are now ripe for such a rebellion. The country voted for Brexit and Chequers is a sellout!” he said.

Banks and his spin doctor Andy Wigmore — two self-styled "bad boys of Brexit” — announced on social media that they had joined the Conservatives, posting their welcome letters.

But a Conservative Party spokesman today said: "Arron Banks and Andrew Wigmore’s applications for membership of the Conservative Party have not been approved.”

The BBC reported citing Conservative sources that the pair were judged likely to bring the party into disrepute.

Wigmore, speaking to Banks’s Westmonster news website, said: "Like thousands of other Brexit supporters I’ve rejoined the Conservative Party to ensure that if there is a leadership contest then I can influence the type of leader the country and the Tory Party need.

"We need a Brexit leader, one who believes in Brexit,” he said.

Banks used to be a Conservative Party member and donor but switched his backing to the United Kingdom Independence Party (UKIP) in 2014.

He then founded the Leave.EU campaign, the biggest unofficial pro-Brexit campaign in the 2016 referendum on Britain’s EU membership. — AFP