Government promises to deliver Brexit and extra cash for public services are expected as the Conservative Party conference begins in Manchester.
On the opening day, ministers have said £13bn will be spent on 40 hospitals across England in the next decade.
The conference takes place amid opposition party threats to stage a no-confidence vote in the government.
Boris Johnson also faces questions over his links with businesswoman Jennifer Arcuri while he was London mayor.
Tory MPs could face travelling between Manchester and Westminster for crucial votes while the conference takes place.
MPs returned to the House of Commons on Thursday 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.
A vote of no confidence in the government, aimed at replacing Boris Johnson as prime minister, could be held next week, one senior SNP MP has said.
Stewart Hosie told the BBC such a move could be the only way to avoid the UK leaving the EU without a deal on October 31.
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.
The government has already announced its intention to spend £13bn on 40 hospital projects in England during the next decade.
The plans include a £2.7bn investment for six hospitals over five years.
A new approach to NHS mental health treatment is also 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.
‘A politically motivated attack’
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 Jennifer 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.
‘A conference like no other’
BBC’s political correspondent Chris Mason said this week’s gathering would be “a party conference like no other”.
“Brexit is a month away – possibly. But the government could face a vote of confidence before then.
“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.”