Raheem Kassam, a former aide to Nigel Farage, has quit the race to become Ukip leader three days after launching his campaign in a Westminster pub.

Update 4.15pm: It is understood that Mr Woolfe passed out after suffering what were described as two "epileptic-like fits" as well numbness on the left hand side of his body.

Nigel Farage’s chief of staff has left his post as the Ukip leader faces rapidly rising pressure to hold on to his job.