Jeremy Corbyn faced demands for an apology after he mistakenly said a police officer who was shot in Belfast had died.
Northern Ireland’s Police Federation led criticism of the Labour leader after his error in the House of Commons.
During Prime Minister’s Questions on Wednesday, Theresa May told MPs her “thoughts were with the family of the officer, his family and friends.”
However, the Labour leader added: “I join the Prime Minister in expressing condolences, I’m sure of the whole house, to the police officer who lost his life over the weekend in Northern Ireland.”
Belfast MP Nigel Dodd was then forced to point out the blunder and said: “Actually, he’s not dead.”
Local MPs criticised the gaffe.
The Ulster Unionist Party’s Tom Elliott tweeted: “Jeremy Corbyn makes huge mistake at PMQ by saying that a police officer lost his life in NI at the weekend. Very poor knowledge or briefing.”
DUP MP Gavin Robinson added there was “fury amongst Labour backbenchers behind us.”
He said: “They were aghast at his ineptitude.”
A spokesman for the Northern Ireland Police Federation called on Mr Corbyn to apologise for the blunder.
He told the Standard: “The officer is seriously injured but is very much alive.
“It is remarkable that the leader of the opposition would get it so badly wrong.”
A tweet posted by the Federation’s Twitter account read: “Disgrace that Labour Leader should get something as serious as this so badly wrong.
“Needs to apologise to officer & family.”
A spokesman for the Labour leader later said: "He meant to say 'nearly died'. Obviously, the last thing that was intended was any offence."