Elizabeth Truss will stay put as environment secretary, the Prime Minister has announced. The Norfolk MP, who was promoted last year, is among a number of David Cameron's top team to have remained in post following the General Election.

Ms Truss become a minister in September 2012, when she was put in charge of childcare. But she was elevated to the top table last summer.

She joined parliament in 2010 after a job as deputy director of the think-tank Reform, where she advocated more rigorous academic standards in schools, a greater focus on tackling serious and organised crime and urgent action to deal with Britain's falling competitiveness.

David Cameron used social media to make the announcement, posting on Twitter: 'Liz Truss will remain as the Secretary of State for the Environment, Food and Rural Affairs.'

Boris Johnson will be a member of Mr Cameron's political cabinet but not a minister, the Prime Minister confirmed, as he appointed the rest of his government.

The newly-elected MP for Uxbridge and South Ruislip walked in through the famous black door carrying his cycle helmet and Mr Cameron swiftly revealed the appointment.

Other Cabinet appointees announced on the first working day of the new Conservative-only Government included Sajid Javid as Business Secretary, in a promotion from culture, media and sport, replacing Vince Cable in one of a number of posts left empty by the end of the coalition with the Liberal Democrats.

Former Commons Culture Committee chairman John Whittingdale replaces Javid as Culture Secretary, with next year's 10-yearly renegotiation of the BBC's Royal Charter at the top of his in-tray. Mr Whittingdale last year described the BBC licence fee as 'worse than a poll tax' and said it was 'unsustainable' in the long run and needed tweaking immediately.

Hastings and Rye MP Amber Rudd is one of a number of women being promoted by Mr Cameron, moving upwards within the Department for Energy and Climate Change from a junior ministerial position to the Cabinet-level Secretary of State role vacated by Lib Dem Ed Davey, who lost his seat last week.

Mr Johnson had not been expected to take a big spending department while serving out his final term as London mayor, and Mr Cameron said that he would 'devote his attention' to his mayoral duties over his remaining year at City Hall.

The political cabinet includes all the key figures at the top of the Government but excludes civil servants as matters discussed are party political. No minutes are taken at the meetings, expected to take place fortnightly at 10 Downing Street following the weekly meeting of the full Cabinet, which formally agrees policy and sits at the heart of government.

Priti Patel will replace Esther McVey, who lost her seat, as Employment Minister. She will attend Cabinet but will hold the rank of minister of state.

And the Prime Minister confirmed Baroness Stowell would be promoted to full Cabinet rank as Leader of the Lords.

Iain Duncan Smith is to remain in charge of the Government's controversial welfare reforms as Work and Pensions Secretary, Mr Cameron has also announced.

The former party leader is one of a number of senior figures keeping their jobs, including Chancellor George Osborne, Home Secretary Theresa May, Foreign Secretary Philip Hammond, Education Secretary Nicky Morgan and Defence Secretary Michael Fallon.

It has already been announced that Michael Gove is returning to the top of government - moving from chief whip to Lord Chancellor and Justice Secretary at the expense of Chris Grayling, who becomes Leader of the House of Commons.

Mark Harper, who quit as immigration minister over the work status of his cleaner, takes over from Mr Gove as chief whip.

Robert Halfon, who was the Chancellor's parliamentary private secretary (PPS) in the last parliament, has been appointed deputy chairman of the Conservative Party.