Britain’s deputy prime minister, Angela Rayner, has stepped down after an investigation found she breached the ministerial code by underpaying property tax, marking a significant setback for Prime Minister Keir Starmer’s Labour government.

Rayner, a prominent voice among Labour’s left-wing supporters, admitted earlier this week that she had not paid enough stamp duty on a flat purchase and voluntarily referred herself to the government’s independent ethics adviser.

In a letter to Starmer, ethics chief Laurie Magnus said Angela Rayner had failed to “heed the caution” of legal advice she previously received and therefore breached the code.

“Given the findings, and the impact on my family, I have therefore decided to resign,” Rayner wrote in her resignation letter, adding she was also stepping down as housing minister and deputy leader of the Labour Party. She expressed “deep regret” for not seeking additional specialist tax advice and said she took “full responsibility for this error.”

Starmer, in his response, said he was “very sad” to lose her but stressed she would “remain a major figure in our party.”

The controversy centers on Rayner’s claim that a flat she purchased was her primary residence, allowing her to pay less property surcharge. However, she later conceded this was incorrect because her under-18 son still lived with her, making the property effectively a second home. Reports suggested she saved around £40,000 ($53,000) through the arrangement.

Magnus acknowledged that Angela Rayner had acted with “integrity and exemplary commitment to public service,” but confirmed that the breach of the ministerial code was clear.

Angela Rayner, 45, has long been viewed as a potential future Labour leader and has faced intense scrutiny from Conservative opponents and right-wing media. Her candid, working-class image has resonated with many voters—she left school at 16 with no qualifications, grew up in social housing in Stockport, and rose to become one of Labour’s most recognizable figures.