A change of guard at the top of the party designed to help it reach out to younger and ethnic minority voters was a major feature of the first day of the Prime Minister’s New Year reshuffle.

However, Mrs May’s bid to reassert her authority was undermined by claims that at least two Cabinet ministers she wanted to move had refused to budge.

And a trying day was finally sealed last night when Education Secretary Justine Greening dramatically quit the Cabinet after refusing to take a new job.

The departure apparently followed long talks in which Ms Greening fought against a move to make her Work and Pensions Secretary.

A Government source said: “Justine was offered DWP but declined to take it. The PM is disappointed but respects her decision to leave the government.”

Jeremy Hunt was said to have persuaded Mrs May in the course of a long conversation to let him keep his job in charge of health, but with his title extended to Secretary of State for Health and Social Care. And Business Secretary Greg Clark kept his post amid rumours he also refused to shift, despite widespread speculation he would be sacked.

Some Tories voiced frustration that in a reshuffle advertised as a bid to make the Government more diverse, Mrs May had “caved in” to two men but not to a woman. And Scottish Tory leader Ruth Davidson pointedly lamented the loss of Ms Greening, who came out as a lesbian in 2016, as a “role model” for gay Conservatives.

But Mrs May kept up female numbers in her Cabinet by making Deputy Chief Whip Esther McVey Work and Pensions Secretary, in a shock promotion. Ms Greening is replaced as Education Secretary by Work and Pensions Minister Damian Hinds.

Meanwhile, the Prime Minister added responsibilities to some of her key ministers to highlight her vow to tackle domestic policy priorities as well as delivering Brexit.

As expected, Sajid Javid remained in place but, reflecting Mrs May’s vow to solve the homes crisis, he heads the Ministry for Housing, Communities and Local Government, previously the Department for Communities and Local Government. Justice Secretary David Lidington replaced Mrs May’s long-time friend Damian Green who quit last month over “misleading statements” over what he knew about claims pornography was found on his office computer.

Former Europe minister Mr Lidington became Minister for the Cabinet Office and will chair many Cabinet sub-committees Mr Green headed, including those related to Brexit. He will also fill in at Prime Minister’s Questions when Mrs May is away, but has not been given Mr Green’s old title of First Secretary of State. Former Work and Pensions Secretary David Gauke becomes the sixth Justice Secretary in eight years.

Chancellor Philip Hammond, Foreign Secretary Boris Johnson, Home Secretary Amber Rudd, Brexit Secretary David Davis and International Trade Secretary Liam Fox all remained in place, as predicted.

Also staying in place was Chris Grayling who remains as Transport Secretary, despite predictions he could be for the chop after criticism of his handling of rail issues. Michael Gove stayed as Environment Secretary, Penny Mordaunt remained Secretary of State for International Development and Gavin Williamson is still Defence Secretary.

A surprise Cabinet departure was James Brokenshire, who resigned as Northern Ireland Secretary the day after his 50th birthday, having learnt in recent days he needs major surgery for a lesion on his right lung.

His politically sensitive job in Belfast, where the DUP-Sinn Fein power-sharing government remains suspended, went to Culture Secretary and long-standing Theresa May ally Karen Bradley.

Ms Bradley’s junior Matt Hancock was promoted to Culture Secretary. Conservative HQ – traditionally known as Conservative Central Office – saw the biggest shake-up. As predicted, veteran MP Sir Patrick McLoughlin lost his job of party chairman after calls for him to be sacked after a poor election campaign cost the Tories their Commons majority last June. A series of basic blunders yesterday almost seemed calculated to underline the need for an HQ overhaul.

The party had problems with its website, reportedly after failing to renew its licence, while the Tories’ official Twitter account briefly and wrongly named Transport Secretary Chris Grayling as new party chairman.

In fact, the chairman’s job had gone to former Immigration Minister Brandon Lewis. But Number 10’s official Twitter account had to delete its initial announcement after misspelling Mr Lewis’s new job title as Minister without Portfolio. His deputy chairman will be former soldier James Cleverly, who has been an MP only since 2015 but is seen as a potential future leader.

Nigerian-raised Kemi Badenoch, 37, and former university drop-out Ben Bradley, 29, become party vice-chairs for candidates and youth respectively.

Their elevation will be seen as a sign of Mrs May responding to calls to promote a new generation of MPs. But pro-abortion choice groups condemned former nurse Maria Caulfield’s appointment as Tory vice-chair for women.

She opposed a fellow MP’s bid to end the criminalisation of women who terminate their own pregnancies. Her promotion to a job representing women was dubbed “appalling” by Labour and “profoundly disappointing” by the British Pregnancy Advisory Service.

Mrs May today plans to complete her Government revamp with a series of changes at middleranking and junior ministerial level, widely expected to include promotions for more women and ethnic minority background MPs at the expense of more established figures.