Julian Smith became the first casualty of Boris Johnson’s Government reshuffle after being unceremoniously dumped from the Northern Ireland Office.
His departure comes just weeks after brokering the deal which restored the powersharing administration in Stormont.
Other senior ministers axed include Andrea Leadsom from her role as business secretary, Theresa Villiers from her post as environment secretary and Esther McVey, who attended Cabinet as housing minister.
Mr Smith said it had been “the biggest privilege” to serve the people of Northern Ireland and he was “extremely grateful” to have been given the chance to serve “this amazing part of our country”.
“The warmth & support from people across NI has been incredible,” he said on Twitter.
“Thank you so much.”
Mr Smith was called in to see the Prime Minister in his Commons office as the reshuffle began.
The Prime Minister intends to “promote a generation of talent” in a reshuffle aimed at preparing the Tories for the future.
Speculation about Mr Smith’s position centred on the terms of the Stormont deal, amid Tory concerns it could pave the way for prosecutions of British soldiers.
But allies of the axed minister said it was “absolute crap” to suggest that Mr Johnson and Number 10 had not been kept informed of the process and details of the deal.
Other ministers thought to be vulnerable are prepared for a “brutal” process as Mr Johnson tries to boost the presence of female MPs in the ministerial ranks.
There is not expected to be a reduction in the number of female members of the Cabinet, even though Baroness Morgan has already said she intends to leave her ministerial role and Ms Leadsom and Ms McVey lost their jobs.
Mrs Leadsom said it had been a “real privilege” to spend six years in Government, adding: “I will continue from the back benches to work to ensure everyone is treated with dignity and respect.”
Ms Villiers said: “What the Prime Minister giveth, the Prime Minister taketh away: just over six months ago, I was delighted to be invited by the Prime Minister to return to government after three years on the backbenches.
“This morning he told me that I need to make way for someone new.”
Fellow former Tory leadership contender Ms McVey said she was “very sorry” to be sacked from her role.
“I’m very grateful to the Prime Minister for having given me the opportunity to serve in his government and he will continue to have my support from the back benches,” she said.
Geoffrey Cox lost his job as the senior law officer, saying: “I am now leaving the Government at the PM’s request.”
Female MPs in line for promotion during the reshuffle process include defence minister Anne-Marie Trevelyan, former Brexit minister Suella Braverman and Gillian Keegan.
Alok Sharma is expected to be promoted from his current Cabinet post at International Development, while Paymaster General Oliver Dowden – who attends Cabinet – is also in line for a bigger job.
A Number 10 source said: “The Prime Minister wants this reshuffle to set the foundations for government now and in the future.
“He wants to promote a generation of talent that will be promoted further in the coming years.
“He will reward those MPs who have worked hard to deliver on this Government’s priorities to level up the whole country and deliver the change people voted for last year.”
The most junior ministerial rank – parliamentary under-secretary of state level – is likely to have a 50-50 gender split after the reshuffle.
By the summer, Mr Johnson also aims to ensure that at least 60% of ministerial aides – the parliamentary private secretaries – will be women, up from 18% at present.
In a sign that male ministers could pay the price, Chris Skidmore indicated he had left his post as Universities Minister to have “more time to spend” with his child.
“Thanks everyone who I’ve had the chance to work with and the civil service teams that have supported me – you have all been amazing,” he said.
Other factors at play in this reshuffle include filling the vacant role in charge of the Cop26 UN climate summit following the sacking of Claire O’Neill and deciding whether Steve Barclay will return to Government after the Brexit department was scrapped following the January 31 departure from the European Union.
Senior ministers including Chancellor Sajid Javid, Home Secretary Priti Patel and Foreign Secretary Dominic Raab are expected to remain in place while Downing Street has confirmed that Grant Shapps will stay on as Transport Secretary.
Mr Johnson’s senior aide Dominic Cummings had reportedly been seeking a wider cull of ministers and a shake-up of Whitehall departments but Number 10 insiders believe a more “conventional” reshuffle will be carried out by the Prime Minister.