Labour's Ken Livingstone has apologised for comments he made suggesting Kevan Jones, the shadow minister for the armed forces, should seek psychiatric help.
The former Mayor of London, who says he was unaware that Mr Jones had suffered from depression, had earlier refused to go back on his comments, despite a call from Labour leader Jeremy Corbyn for him to do so.
In an earlier interview with ITV News Deputy Political Editor Chris Ship, Mr Livingstone finally offered an apology, of sorts, saying, "If Jeremy wants me to apologise I'm happy to do so."
Asked if that was an apology, the former London mayor said: "That's the best you'll get out of me."
However, shortly after the interview he appeared more remorseful, tweeting his "unreserved" apologies for the comments.
The row with Mr Jones erupted after the shadow shadow minister for the armed forces, who backs maintaining Trident, criticised Mr Livingstone's appointment to lead a review of Labour's position on the UK's nuclear deterrent.
Mr Livingstone said Mr Jones was "disturbed" and "might need some psychiatric help".
Among the critics of the comments was former Labour spin doctor Alastair Campbell, who himself has spoken of his struggle with depression in the past.
Mr Corbyn had asked Mr Livingstone to apologise for the remark as he was keen that people with mental health problems should not be stigmatised, a spokesman for the Labour leader said.
In his interview with ITV News Mr Livingstone said he was unaware that Mr Jones had suffered from depression, adding: "This guy shouldn't pick a fight with people and then start whimping around."
He insisted he was not stigmatising people with mental health problems, saying he knew very little about Mr Jones and was simply "being rude about a Labour MP who is being rude to me".
But he added that: "Anyone who wants nuclear weapons is mad."
Mr Jones, along with a number of other Labour MPs, are in favour of keeping Trident, in opposition to Mr Corbyn and Mr Livingstone, who have both made clear they opposed to it.