Reform UK’s new chairman once called leader Nigel Farage an ‘idiot’, it emerged last night.

Dr David Bull, who was unveiled as Zia Yusuf’s replacement, also branded as ‘prejudiced’ comments that Mr Farage had made about HIV-infected migrants using the NHS.

The remarks surfaced just hours after Dr Bull gave his maiden speech as chairman and threatened to overshadow his appointment, while at a Press conference unveiling the new chairman, Mr Farage unexpectedly ruled out putting the return of the death penalty on Reform’s manifesto at the next general election.

Dr Bull’s comments, first reported by The Daily Telegraph, were made on social media in 2014. He posted them after Mr Farage, then leader of his previous party UKIP, suggested that HIV-positive immigrants should not be allowed to come to the UK and receive treatment on the NHS.

He said it should not be used as a ‘global health service’, adding: ‘I do not think people with life-threatening diseases should be treated by our National Health Service, and that is an absolute essential condition for working out a proper immigration policy.’