At the opening of a “critical” week for the country and the Prime Minister, Brexit is at the top of the agenda for most of Monday’s papers.

The Guardian says Theresa May is facing what may be the most perilous week of her premiership as she tries to fend off attacks on her plan from Tory rebels.

The Metro carries the PM’s warning that removing her from No 10 would create damaging uncertainty.

Amid rumours of hardline Brexiteers organising to unseat her, former Tory chief whip Andrew Mitchell has warned against a leadership challenge, The Times reports.

The i reports on speculation over who may succeed the PM.

The Daily Telegraph says Mrs May will take on Brexiteers in her Cabinet on Monday to tell them that the withdrawal agreement she has negotiated is final.

In a speech she will insist the deal will give Britain back control of its borders and allow the introduction of a skills-based migration system, the Daily Express says.

In other Brexit news, the Army has been put on standby in case their help is required in the event of no-deal, according to the Daily Mirror.

And the Financial Times reports that the EU could extend the transition period until 2022 in order to secure a trade deal with the UK.

Away from Brexit, The Sun says five soldiers from the Queen’s Guard were arrested after an alcohol-fuelled fight near Windsor Castle.

The Daily Mail says the backgrounds of some 3,000 foreign NHS doctors are being reviewed after it emerged a woman with no qualifications was able to work as a psychiatrist for more than 20 years.

And the Daily Star says Declan Donnelly has voiced his support for Ant McPartlin as he kicked off I’m A Celebrity without his usual co-host.