Steven Woolfe, the Ukip MEP who was recently hospitalised following an altercation with a fellow MEP in the EU parliament, has resigned with immediate effect. Woolfe, who was recently the favourite to take over from Diane James as the new leader of the party, said he is quitting the party as it is "ungovernable without Nigel Farage leading it and the referendum cause to unite it".

Woolfe named Ukip defence spokesman Mike Hookem as the man he was in an "altercation" with, which saw him collapse in the EU Parliament building in Strasbourg. Hooken denied hitting Woolfe after he had told him to "step outside" following an argument believed to have stemmed from Woolfe saying he considered defecting to the Tory party.

Woolfe also confirmed he has made a complaint to the police over the alleged incident in Strasbourg.

Confirming his resignation, Woolfe said: "Six years ago, I joined Ukip. Since then, I have campaigned with all my energy, time and determination to champion the party's core beliefs and values.

"I have been proud to stand in local, general, PCC and London assembly elections – and of course to be elected as a North West MEP.

"I have been proud to be a part of the team led by Nigel Farage, one of Britain's greatest ever politicians. He brought me into the party and helped us win the referendum – a moment I will always treasure. Without Nigel, the donors, the team members and the activists, the UK would not be free today.

"It was because of the support from party members that I put my name forward to lead the party in the summer, and again two weeks ago following Diane's resignation. However, I could not have foreseen the events that would follow.

"The events at the meeting in Strasbourg led to me later being treated by doctors for two seizures, partial paralysis and loss of feeling in my face and body.

"I would like to thank all of the medical staff in Strasbourg for their impressive and swift treatment. I owe them my life. I would also like to thank my family and friends for their love and support – and also all of the people in politics who have sent me their best wishes.

"Since then, I have spent some time considering my personal and political future.

"It is with deep sorrow and regret that I am aborting my leadership campaign and announcing my resignation from Ukip with immediate effect.

"I believe that a strong Ukip would hold this government's feet to the fire and make sure it delivers a clean Brexit. However, I have come to the conclusion that Ukip is ungovernable without Nigel Farage leading it and the referendum cause to unite it."

Steven Woolfe
UKIP MEP Steven Woolfe face down on a floor at the European Parliament in Strasbourg, France ITV News / Reuters

Woolfe added: "The way I was treated by members of my own party during the summer's leadership campaign and the events that have led up to today have all contributed to me coming to this conclusion. The party is riddled with infighting, proxy wars between rival camps and is run by an NEC that is not fit for purpose.

"Once my recovery is complete, it is my intention to sit as an independent MEP in the European Parliament.

"I will continue to represent my constituents in the European Parliament until the UK's exit from the EU in 2019. I will champion the values I hold dear – those of freedom, democracy and an independent United Kingdom.

"With regards to the highly regrettable events in Strasbourg, I will reiterate my position that I received a blow from Mr Hookem that knocked me back into the meeting room and caused my subsequent injuries. Contrary to reports, I have made a police complaint.

"I am now seeking legal advice in respect of the investigations and will not be commenting further on the matter until the completion of those investigations."

The news comes after Ukip confirmed that ballots will be sent to their members to vote on who they want to be their new leader on 11 November, with the decision expected to be announced on 28 November.

Fellow MEP Bill Etheridge announced he will stand in the leadership election, as well as Raheem Kassam, former leader Nigel Farage's chief of staff. The party's former chair, Suzanne Evans, is also considering running in the election.

Steven Woolfe
Nigel Farage (R) arrives with Steven Woolfe (L) to a conference in which the party's immigration policy was unveiled on 4 March, 2015 Carl Court/ Getty Images