Deputy Labour leader Angela Rayner has apologised for branding senior Tories “scum”.
The comments, at a reception at Labour’s conference in September, drew condemnation from senior Conservatives.
Ms Rayner said: “I would like to unreservedly apologise for the language I used, and I would not use it again.”
Sir David Amess
Her apology followed a period of reflection while off work following a bereavement.
It also came after she was targeted by threats and at a time when Westminster is still mourning the loss of Sir David Amess, who was stabbed to death at a constituency surgery.
“While I have been away from the cut and thrust of Parliament I have reflected on our political debate and the threats and abuse that now seem to feature all too often,” Ms Rayner said.
“I have also reflected on what I said at an event at Labour Party conference.
“I was angry about where our country is headed and policies that have made life harder for so many people I represent.
“But I would like to unreservedly apologise for the language I used, and I would not use it again.
“I will continue to speak my mind, stand up for Labour values and hold the Government to account.
“But in the future I will be more careful about how I do that and in the language that I choose.”
A former delivery driver who sent a threatening email to Ms Rayner was handed a suspended sentence on Thursday.
The court heard Benjamin Iliffe, 36, send the message because he felt she was “partially responsible” for the attack on Sir David after she called the Conservative Party “scum”.
The defendant, who appeared by video-link from Thorpe Wood police station in Peterborough, Cambridgeshire, warned Ms Rayner to “watch your back and your kids” in the email.
He admitted sending a threatening email, and also pleaded guilty to possessing a quantity of cannabis on Wednesday when he was arrested.
Iliffe, of Chatteris in Cambridgeshire, was sentenced to 15 weeks in prison, suspended for 18 months at the hearing at Huntingdon Magistrates’ Court.
At the Labour conference, Ashton-under-Lyne MP Ms Rayner described the Tories as “a bunch of scum, homophobic, racist, misogynistic”.
Labour leader Sir Keir Starmer said he would not have used those words and spoke to Ms Rayner about the comments during the Brighton conference.
Following Thursday’s events in court, Sir Keir said: “It is shocking and appalling that Angela Rayner has suffered threats against her and against her family.
“Solidarity to Angela from me and the whole party.”