The Conservative Party conference will begin in Manchester later following a turbulent week for Boris Johnson.
The PM faced stormy scenes in Westminster after a ruling by the Supreme Court that his suspension of Parliament was unlawful.
Rows later broke out over Mr Johnson’s use of language in the Commons, and questions over his links with US businesswoman Jennifer Arcuri.
But he will now try to focus on Brexit and promises for public services.
On the opening day, ministers have promised to spend billions on hospital projects across England in the next decade.
But opposition MPs back in London could stage a no-confidence vote in the government.
Senior SNP MP Stewart Hosie told the BBC such a move may be the only way to avoid the UK leaving the EU without a deal on October 31.
Tory MPs could face travelling between Manchester and Westminster for crucial votes while the conference takes place.
Speaking to the BBC’s Andrew Marr Show ahead of the conference opening, Mr Johnson defended the use of words including “surrender” during heated Parliamentary debate.
He has referred to the Benn bill, which is designed to force the PM to seek an extension rather than lead the country into a no-deal Brexit, repeatedly as “the surrender bill”.
Mr Johnson was widely criticised for his use of language earlier this week by some MPs, especially women, who said the use of such terms was inflaming tensions and contributing to threats made against them.
He said any such threats were “deplorable” but he did not regret “using the word surrender to describe the surrender act”.
“Military metaphors are old, standard, Parliamentary terms,” he continued, and stopping politicians from using them would “impoverish debate”.
“I think everybody should calm down,” he said, but asked whether that included him, he added: “I think I’ve been the model of restraint.”
MPs returned to the House of Commons on Wednesday after the Supreme Court ruled the government’s suspension of Parliament was unlawful and No 10 later failed to secure a recess for the conference.
Labour leader Jeremy Corbyn is expected to bring opposition leaders together at a meeting in Westminster on Monday to plan their next steps to avert a no-deal Brexit.
Mr Corbyn has said he would be ready to become a caretaker PM if Mr Johnson was forced from No 10.
As well as promises on hospitals, the government is also announcing a new approach to NHS mental health treatment to be trialled in 12 areas of England – with housing and job support alongside psychological help.
Chancellor Sajid Javid is expected to speak on Monday and Home Secretary Priti Patel – talking about tackling crime – on Tuesday.
Animal welfare policies, environmental plans – including a proposed £1bn fund to boost the electric motor industry and a pledge to plant one million new trees – are on the agenda.
This is a party conference like no other.
Brexit is a month away – possibly. But the government could face a vote of confidence before then.
And as activists and MPs gather here, Parliament continues to sit at Westminster, with the potential that the opposition parties do their best to make life awkward for the Conservatives, by hauling their MPs 200 miles south for votes.
Brexit, inevitably, dominates. But Boris Johnson and others will endeavour, at least, to broaden the conversation – to set out a platter of other policies they hope might prove appetising to voters at a general election.
They’ll aim to portray Parliament as a pointless talking shop – “blocking everything and trying to delay Brexit” as a source put it – and to portray themselves as the only party that can get Brexit done.
But the last few weeks have made on thing abundantly clear – the prime minister is in office, but barely in control.
A small group of anti-Brexit protesters gathered near the conference venue on Saturday evening as Mr Johnson arrived in Manchester with his partner, Carrie Symonds.
Meanwhile, the Sunday Times has fresh allegations about the American businesswoman at the centre of claims about her links to the prime minister.
The paper claims that Jennifer Arcuri told four friends that she had an affair with Mr Johnson while he was mayor of London.
On Friday, the Greater London Authority (GLA) referred Mr Johnson to the police watchdog over allegations Ms Arcuri, a US technology entrepreneur, received favourable treatment because of her friendship with him while he was mayor of London.
Ms Arcuri joined trade missions led by Mr Johnson while he was mayor and her company received several thousand pounds in sponsorship grants.
The Independent Office for Police Conduct (IOPC) will now consider whether there are grounds to investigate the Prime Minister for the criminal offence of misconduct in public office.
Mr Johnson has denied any impropriety, with the move later branded as “a politically motivated attack” by a senior government source.