Woolfe, a member of the UK Independence Party (Ukip) collapsed, after a dispute with fellow-Ukip MEP Mike Hookem, during a group meeting in the European Parliament in Strasbourg.

"Mike came at me and landed a blow. The door frame took the biggest hit after I was shoved into it," Woolfe told the Daily Mail , adding that he banged his head as he fell. Hookem denied hitting Woolfe or seeing him hit his head.

The argument started because Woolfe, a contender to the UKip leadership, admitted he had considered joining the Conservative Party. 

Woolfe will remain at the hospital in Strasbourg until Sunday.

"The reported facts are extremely serious. It goes without saying that disrespectful and violent behaviour does not have a place in the European Parliament," Schulz said.

The advisory committee, which is composed of five MEPS - Danuta Huebner, Mady Delvaux, Sajjad Karim, Jean-Marie Cavada and Jiri Mastalka - will have a first meeting on Wednesday (12 October).

They will hear from Woolfe, Hookem and "whoever they deem appropriate," like other MEPs or staff who were at the Ukip meeting or outside the room, a parliament official told EUobserver.

They will issue a report to set straight the facts, but they will not issue any recommendation on sanctions. The decision will be taken by Schulz on the basis of the report.

Schulz, if he finds it is necessary, could also meet with both Woolfe and Hookem to get their version of events.

Both MEPs risk being stripped of their basic allowance and suspended for two-to-ten working days.

Meanwhile, Ukip's interim party leader Nigel Farage said that the party will also hold its own investigation into the incident. He called claims being made in the media "by representatives of Ukip who were not even there at the time" as "extremely unhelpful".

On Friday, another Ukip MEP, Nathan Gill, said after visiting Woolfe that the injured MEP had "reached out a hand of friendship" to Hookem.