LONDON — A U.K. Independence Party legislator who was hospitalized after an altercation with a colleague announced Monday he is quitting the feuding right-wing party, which played a key role in the country’s decision to leave the European Union.

Steven Woolfe, who had been a UKIP leadership contender, said he has made a police complaint about the Oct. 6 fracas at the European Parliament.

Woolfe claims he “received a blow” from fellow UKIP legislator Mike Hookem during an argument at a meeting of UKIP European parliamentarians at the bloc’s legislature in Strasbourg, France.

Woolfe collapsed a short time later and was hospitalized for several days. He said he had suffered “two seizures, partial paralysis and loss of feeling in my face and body.”

Hookem denies hitting Woolfe. He said Monday that Woolfe had shown “disloyalty to the UKIP party and membership” by holding talks about joining the much larger Conservative Party.

A small, anti-EU party, UKIP was instrumental in getting Britain to hold a referendum on European Union membership, which ended in a June 23 vote to leave the 28-nation bloc. The result was a political triumph for UKIP, but the party has been torn by infighting since gaining its long-sought goal.

UKIP has been trying to find a replacement for outgoing leader Nigel Farage. The first leader chosen, Diane James, resigned after less than three weeks in the position.

The party said Monday it will announce its new leader Nov. 28. Farage is serving as interim leader.