Labour's deputy leader Angela Rayner has apologised "unreservedly" for calling Conservatives "scum" during her party's conference in Brighton last month.
In a lengthy statement posted to her social media accounts, Ms Rayner said she would not use the same language again having "reflected" in recent weeks.
The Ashton-under-Lyne MP has been away from Westminster over the last two weeks following the death of a loved one.
And she said she had used the time away from the "cut and thrust" of parliament to consider "our political debate and the threats and abuse that now seem to feature all too often".
It came hours after a court sentenced a man for sending a threatening email to Ms Rayner.
When first quizzed about her "scum" comments, made during an evening event at Labour's Brighton conference in September, Ms Rayner had initially refused to apologise.
But, in the statement she shared on Thursday evening, the Labour frontbencher said: "I have reflected on our political debate and the threats and abuse that now seem to feature all too often.
"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.
"All of us in positions of leadership have a responsibility for our language and rhetoric, whether towards political opponents or anyone else in society, especially those already most vulnerable."
Ms Rayner also used her social media statement to address the killing of Conservative MP Sir David Amess, whose death prompted a wider discussion over threats and hostility faced by politicians.
"Grief is the burden we bear for love and losing someone close is something that we all experience at some point in our lives, but that knowledge doesn't make it any easier when it happens to you," she said.
"So I can't imagine what the family of Sir David Amess are going through, but I know they will be hurting.
"I send my heartfelt condolences to them. Sir David was a fine parliamentarian, a proud advocate for his constituents and above all such a kind, generous and warm-hearted man."
The Labour deputy leader also commented on the threats she herself has received.
"In the past I have been reluctant to speak out about the abuse that I receive because I fear that doing so will only make the situation worse," she said.
"However, in recent weeks the threats that I have received against my life and the lives of close family have been so terrifying and explicit that I could not stay silent and simply continue to take it as 'part of the job'.
"They have had a devastating impact on me, my children and others close to me."
Ms Rayner admitted she had been "shaken" by the threats she received, adding: "My staff come to work and do their jobs with dedication and professionalism.
"They bear the brunt of much of this abuse and then get on with their working day. Dealing with death threats and liaising with the police about their safety should not be a standard part of the day-to-day working life of an MP or their staff."
She thanked police for their "utmost professionalism, courtesy and kindness both in carrying out their investigations and in supporting me, my family and my staff during what has been a very difficult time".
Ms Rayner's comments at the Labour conference were widely condemned by Tories, while Labour leader Sir Keir Starmer and other members of the party's front bench said they would not have used the same language to describe political opponents.
During the evening conference event in September, Ms Rayner told an audience: "We cannot get any worse than a bunch of scum, homophobic, racist, misogynistic, absolute vile … banana republic, vile, nasty, Etonian… piece of scum."
And she added she had "held back a little".