Britain First has boasted the number of applications to the group has soared in the wake of Donald Trump re-tweeting a number of videos by one of its members.
The leader of the group, Paul Golding, said its social media following had gone stratospheric as the row between the US President and Theresa May continues to unfold.
The argument began after the US President retweeted three anti-Muslim videos posted by Jayda Fransen, the group’s deputy leader.
Theresa May said via a spokesman Trump was wrong to do this, which prompted him to hit back at the Prime Minister on Twitter.
Golding, who is facing charges of religiously aggravated harassment alongside Jayda Fransen, said the row had boosted Britain First's popularity.
Speaking to The Times, he boasted the interest in the group had risen exponentially as a result of the endorsement from the US President.
However the paper also reports that Golding is being investigated over an alleged sexual assault at a hotel in Oldham in July.
The alleged victim has reported Golding to the police, claiming he assaulted her after a rally against Muslim sex gangs.
A Greater Manchester Police spokesman said: 'On Thursday 7 September 2017, police received a report of a sexual assault which had happened on Saturday 22 July 2017 in Oldham.
'A 25-year-old woman had been staying at a hotel on Grains bar. Enquiries are ongoing to establish the full circumstances around this incident.
'Anyone with information is asked to contact police on 101, quoting crime reference number 251348J/17.'
Golding has denied he was arrested in an interview with MailOnline.
Meanwhile the diplomatic row sparked by Trump's tweets is reported to be escalating, after the UK ambassador in Washington, Sir Kim Darroch, said he had raised the concerns of the Government with the White House.