Steven Woolfe, who turned 49 on Thursday, is a member of the European Parliament for England's north-west, and the party's migration spokesman.

UKIP leader Nigel Farage said he would launch a party inquiry into what he called an "altercation" between "two grown men" at the meeting, but declined to name the other person involved.

The BBC reported that Mr Woolfe collapsed two hours after "punches were exchanged", citing party sources. Mr Woolfe confirmed later that he had two 'epileptic-like fits' and numbness on the left hand side of his body at 12.30pm when he collapsed and passed out.

Mr Woolfe told the UK's Daily Mail that party defence spokesman Mike Hookem "came at me and landed a blow".

"Mike was obviously very angry and lost his temper," Mr Woolfe told the Mail from his hospital bed.

However Mr Hookem strenuously denied punching his colleague and his allies accused Mr Woolfe of tripping over.

Mr Woolfe, the Mail reported, challenged his fellow MEP to 'step outside' and settle their differences 'man on man'. Both took off their jackets. Mr Woolfe told the Mail: "I wasn't bruising for a scrap. I asked to deal with the matter outside of the room because it was flaring up in the meeting and upsetting everybody, and Mike clearly read that totally the wrong way. It was a completely unexpected incident.

"Mike came at me and landed a blow. The door frame took the biggest hit after I was shoved into it and I knew I'd taken a whack and was pretty shaken."

Mr Woolfe said he banged his head as he fell. Mr Hookem said: "I did not hit Steven and I did not see him hit his head."

The men retrieved their jackets and went back to the meeting. Two hours later, Mr Woolfe said, "I began feeling woozy and knew something wasn't right so I ran out to get help. I started shouting, 'Where is the medical centre?' and was pointed over a walkway bridge. "That's the last I can remember. I don't remember anything else.Next thing I know, I woke up surrounded by Parliament staff, lying on the floor and they ran to get my colleague Nathan Gill, who then came with me to the hospital.

"The doctors told me I had had one seizure lasting three minutes and then another."

Amid speculation about the seriousness of his condition, the party issued a statement on Thursday afternoon from Mr Woolfe himself, confirming he had been admitted to hospital and saying he had undergone a CT scan, but saying that he was now feeling fine apart from some "numbness" on one side of his face.

The statement read: "The CT scan has shown that there is no blood clot in the brain. At the moment I am feeling brighter, happier and smiling as ever. As a precaution, I am being kept in overnight awaiting secondary tests to make sure everything is fine."

"I would like everyone to know that the parliamentary staff, the UKIP MEPs with me and the hospital staff have been brilliant. Their care has been exceptional. I am sitting up, and said to be looking well. The only consequence at the moment is a bit of numbness on the left hand side of my face."

ITV showed footage of Mr Woolfe sprawled face-down on a Strasbourg parliament walkway, his briefcase still in his hand. One source said he had complained of losing feeling on one side of his body before the collapse.

Mr Farage condemned the incident as bad for UKIP's image.

"It's made us look like we're violent," he said. "It's not good." Mr Woolfe was expected to make a full recovery, Mr Farage said, adding that he did not expect the matter to be referred to French police.

Roger Helmer, UKIP MEP for the East Midlands, said the MEP collapsed two hours after a "lively exchange of views" in a party meeting in Strasbourg. It had been intended as a 'clear the air' meeting with MEPs unhappy with Mr Woolfe's glowing praise for new Prime Minister Theresa May.

MEPs had met later for a voting session, which Mr Woolfe had left shortly before he collapsed.

UKIP's Welsh leader Neil Hamilton, who was not at the meeting but said he had been given an account of what had happened by an eyewitness, said Mr Woolfe had been knocked over and hit his head on a window.

A spokeswoman for the national police in France told Press Association: "No one has called us about this incident and so we have no plans to investigate it at this time. If someone decides to ring and make a complaint, we will of course follow it up."

It is the latest, literal blow to a party that has fractured into squabbling factions since the Brexit referendum. UKIP's new leader Diane James quit on Tuesday evening after just 18 days in the job.

Mr Woolfe had announced he would stand for the leadership. He had been favourite to win in the previous ballot in August, but was disqualified for filing his official application too late. He has the backing of former (and now temporary returned) UKIP leader Nigel Farage, and the party's major donor Arron Banks.

However he angered many UKIP members by admitting he had considered joining the Conservatives after being "enthused" by new Prime Minister Theresa May.

In his statement announcing his candidacy, Mr Woolfe said "Her support of new grammar schools, her words on social mobility and the growing evidence that she is committed to a clean Brexit prompted me... to wonder whether our future was within her new Conservative Party".

Shocked UKIP MEPs tweeted their best wishes to Mr Woolfe for a quick recovery.

with Reuters