Angela Rayner has declined to apologise for calling the Conservatives "scum", saying she was using "street language" to convey her "anger and frustration" at the actions of the government.
Speaking to Trevor Philips on Sunday on Sky News, Labour's deputy leader said the comments were made "post-watershed as we would say, with a group of activists at an event last night" at the party's annual conference in Brighton.
"What I was trying to get across, and it is my passionate way in which I do it, is the anger and frustration that people feel when you have a prime minister, who has said things and not apologised that are racist, that are misogynistic, that are homophobic, that has given billions of pounds of taxpayers' money to their mates and literally wasted that money," Ms Rayner said.
"At a time when they're cutting Universal Credit, plunging families into crisis and the cost of living is going up. My passion was about look, we can't sit on the sidelines here, we have to get organised.
"I was speaking to a group of activists to say you've got to get that fire in your belly."
Labour's deputy leader said she was referring to Boris Johnson and his top team of ministers when making the remark.
And she doubled down on it, declaring: "I think anyone who leaves children hungry during a pandemic and can give billions of pounds for their mates on WhatsApp, I think that was pretty scummy.
"It's a phrase you would hear very often in northern working class towns, that we'd even say it jovially to other people, we say it's a scummy thing to do.
"That to me is my street language, as you would say, about actually it's pretty appalling that people think that's OK to do."
Ms Rayner stresses she was not saying that anyone who voted for the party was "scum", adding: "I'm not saying anybody who voted Conservative are those things, I'm saying the prime minister has said those things and acted in that way.
"If the prime minister wants to apologise and remove himself from those comments that he's made that are homophobic, that are racist, that are misogynistic then I will apologise for calling him scummy."