Labour’s shadow culture secretary has refused to back a controversial claim in one of the party’s online adverts suggesting Rishi Sunak does not want child sex abusers to be jailed.

Lucy Powell repeatedly distanced herself from the tweet posted from the Labour Party’s official Twitter account during a TV interview round, and did not endorse its central claim.

The Labour advert says next to an image of Mr Sunak: "Do you think adults convicted of sexually assaulting children should go to prison? Rishi Sunak doesn't."

It then notes that under the Tory government 4,500 adults convicted of sexually assaulting children aged under 16 served no prison time.

'Gutter' politics

The advert has been condemned as a "dog whistle" and "gutter" politics, with criticism from both Tory and Labour figures since it was posted on Thursday, but remained online as of Friday morning.

A Twitter explanatory note has been attached to the tweet with context, noting current sentencing guidelines for this crime has a maximum sentence of 14 years imprisonment.

Ms Powell, who is in Sir Keir Starmer’s shadow cabinet, was grilled about the advert as she gave broadcast interviews on Friday morning.

Asked on BBC Breakfast if she stood by the Twitter post’s core claim, Ms Powell said: "What I stand by is what that graphic is trying to show, which is that the prime minister of our country is responsible for the criminal justice system of our country - and currently that criminal justice system is not working."

Asked whether she stood by the message, she said: "I stand by what this tweet and this campaign is trying to highlight.

"The graphic itself, obviously, is a skit based on his own graphics that he extensively uses," she added.

"I can see it's not to everybody's taste and some people won't like it.

"I didn't design the graphic but I'm here to explain what lies beneath it - which is a very serious point about what is happening to our criminal justice system, which is pretty shocking."

'I didn't design it. I didn't, put it up there'

There were similar exchanges in her interview with GB News, where Ms Powell said: "It's a digital campaigning graphic. I didn't design it. I didn't, put it up there.

"But it's a digital graphic that's based on - it's like a skit, if you like, or a take on the types of graphics that the Prime Minister himself produces about his own policies and he's become famous for producing."

Political backlash over the advert has continued to build.

John McDonnell, the Labour MP and former shadow chancellor, said: "This is not the sort of politics a Labour Party, confident of its own values and preparing to govern, should be engaged in. I say to the people who have taken the decision to publish this ad, please withdraw it. We, the Labour Party, are better than this."

Lee Anderson, the Tory deputy chairman, called it "vile and desperate". Rory Stewart, the former Tory justice minister, called it "bile", adding: "It’s bad policy and nasty politics."

By 11am on Friday the tweet had not been deleted.