Theresa May rules out Cameron-style return to frontline politics

The former prime minister said she would have “plenty to do” when asked if she would follow in the steps of her predecessor, who returned as Foreign Secretary having been ennobled as Lord Cameron.

Mrs May also appraised the careers of two of her successors as premier – Boris Johnson and Rishi Sunak – but offered no comment on Liz Truss’s time at Downing Street.

Speaking at a Chatham House event, Mrs May was asked by an audience member whether she would consider a return to frontline politics.

She replied: “What has triggered my decision to step down at the next election is that I set up a global commission on modern slavery and human trafficking last October.

“I have just spent a day in New York at the United Nations talking about that global commission with some of my fellow commissioners and it is taking more time than I expected.

“That is why I am stepping down from Parliament, so I think I am going to have plenty to do, thank you.”

Asked what her advice for Rishi Sunak would be as he mulls over when to call a general election, she replied: “Don’t go walking in Wales.”

The former premier also spoke about Mr Sunak and Mr Johnson’s time in power.

“Boris obviously was the one who took the strong stance on Ukraine, but on the other hand he was also the one who was willing to put through proposed legislation which, in my view, in relation to the Northern Ireland Protocol, was breaking the international treaty and breaking international law,” she said.

“I think the critical thing that Rishi has done is to be able to stabilise things here in the United Kingdom and to genuinely – because I think our relations with our European allies and our geographically closest allies are important – I think he has been able to improve those relations significantly and I think that is important for our future.”

Mrs May did not offer any comment on Ms Truss’s short time in office.

She also appeared critical of Brexit-supporting Tory colleagues when asked what three things she would do differently as prime minister.

Referring to her proposed Brexit deal, she told the audience: “I had assumed that voters who had voted in the party in Parliament, who had voted for Brexit, would vote for a Brexit deal. I hadn’t realised the extent to which they wanted a very specific Brexit deal, so I think that is one of the things I would do.”

The Maidenhead MP said she would have tried to “move more quickly on mental health”, adding: “We still haven’t got it on the statute book and so it will be to the next government to bring in that new mental health act.”

A “harder” push on the UK’s industrial strategy was also among her unrealised ambitions.

In the wide-ranging interview, Mrs May also offered her views on the potential return of Donald Trump to the White House.

She said a new Trump presidency was “likely to be unpredictable”, particularly in regard to the US commitments to the Nato defence alliance.

Mrs May added: “As I said earlier, he was right that we want all Nato members to be paying their share, but he did commit to Nato.

“He has now made some anti-Nato statements, he’s reported as making some pro-Nato statements, so I think if he were back in the presidency, I am not sure that we absolutely know which way that would go.”