THERESA May has urged the Conservative Party to come together to “truly unite our party and our country” as she ruled out a snap general election and made clear her aim was not just to win the poll in 2020 but to “win big”.

As the removal vans arrived in Downing Street to help with David Cameron’s departure, the incoming prime minister paid a visit to Tory HQ in central London, telling staff that it was "an honour and a privilege to be the new leader of this great party".

Mrs May told party workers Labour had brought Britain to the brink of bankruptcy and could never be allowed to do so again.

"Whether it's led by Tony Blair, Gordon Brown or Jeremy Corbyn, when Labour prospers, the country suffers. So let's make sure they don't prosper.

"Let us redouble our efforts and let us make sure we put this time to good use, to build the support we need to go to the country in four years' time, and not just win, but win big," she declared.

After the formal process today of one PM leaving No 10 and another taking over following visits to the Queen at Buckingham Palace - Mr Cameron is due there at 4pm - Mrs May will begin the not inconsiderable task of forming her new government.

Heavily tipped to enter the Treasury as chancellor is Philip Hammond, who backed Mrs May early on. A former shadow chief secretary, as defence secretary he balanced the books at the start of the Coalition government, filling in a £38 billion black hole. Being chancellor is a job Mr Hammond has long coveted.

George Osborne could do a job swap with Mr Hammond and transfer to the Foreign Office.

Senior Brexiter Chris Grayling will be rewarded for his role running Mrs May's campaign, possibly replacing her as Home Secretary.

While the new PM will be in charge of the Brexit negotiations, the day to day work will be in the hands of a cabinet minister dedicated to the task of taking Britain out of the EU. This role could be filled by lead Leaver Andrea Leadsom, who is expected to be offered a top job in recognition of her raised profile during the referendum.

But big question marks are hanging over the future of Brexit standard-bearers Boris Johnson and Michael Gove, who were seen to have blotted their copy-books in the wake of the referendum result but moved quickly to endorse Mrs May when Mrs Leadsom pulled out.

Liam Fox, the former defence secretary, who was the first leadership contender to be eliminated, quickly swung behind Mrs May. Despite his high-profile departure from cabinet in October 2011, the former GP has behaved himself on the backbenches. The leading Outer looks set for a Cabinet return, possibly replacing Jeremy Hunt, who has antagonised the striking junior doctors, at health.

Northern Ireland Secretary Theresa Villiers - one of a handful of Cabinet ministers who backed Leave - could be for the chop to make way for some new faces.

Meantime, as the only Scottish Conservative MP David Mundell, another May supporter, looks certain to remain at the Scotland Office; his key role could be staving off the prospect of a second Scottish independence referendum.

The first cabinet appointments could come as early as this evening with others made tomorrow. More junior appointments are likely to be made over the weekend with Mrs May making her debut at PMQs next Wednesday before Westminster rises for its summer recess.