Boris Johnson’s decision to sack Julian Smith as Northern Ireland Secretary showed the Prime Minister’s "dangerous indifference" to the region's people, the leader of the Nationalist SDLP party has claimed.

During his seven months at the Northern Ireland Office Mr Smith helped to secure the restoration of Stormont.

Colum Eastwood took to Twitter to express his disappointment: "Thank you @JulianSmithUK for your tireless commitment to devolution, for the work you've done for victims of historical institutional abuse & for securing much needed resource for Derry.

READ MORE: Andrea Leadsom and Northern Ireland secretary out in cabinet revamp

"Sacking the most successful SoS in a decade shows Johnson's dangerous indifference to us."

Earlier, Marty Adams of historical abuse victims campaign group Survivors Together said the sacking of Mr Smith, who helped broker the deal to restore the Stormont administration, would be "disastrous", adding: "We won't find his like again."

Scots-born Mr Smith, who is MP for Skipton and Ripon in Yorkshire, reacted to his dismissal on social media, saying: "Serving the people of Northern Ireland has been the biggest privilege. I am extremely grateful to @BorisJohnson for giving me the chance to serve this amazing part of our country. The warmth & support from people across NI has been incredible. Thank you so much."

Arlene Foster, the leader of the Democratic Unionist Party, paid tribute to Mr Smith, saying his dedication to the role was "incredible".

She tweeted: "Spoke with @JulianSmithUK a short time ago to thank him for his help in getting devolution restored. We may not have always agreed (we did sometimes) but his dedication to the role was incredible. Best wishes to him and his family. Always welcome in Fermanagh."

Simon Coveney, Ireland's Deputy Prime Minister, tweeted a reply to Mr Smith’s Twitter message, saying: "U have been such an effective SOS for NI at a time of real challenge & risk.

"Without your leadership I don't believe NI would have a Govt today. Thank you @JulianSmithUK for your trust, friendship and courage; UK & #Ireland can look to future with more confidence because of it."

Among the other casualties – their fate announced privately to them from Mr Johnson’s Commons office – were Andrea Leadsom, Theresa Villiers, Esther McVey and Geoffrey Cox.

Mrs Leadsom, who served as Business Secretary, said it had been a “real privilege” to serve in Government for the last six years, including at the Business Department for the last six months.

“I now look forward to focusing on my constituents and on my 20+ year campaign to see every baby get the best start in life. I'm particularly proud of my work in BEIS on net zero and the #CountDowntoCOP and on making the U.K. the best place in the world to work and to grow a business. Huge thanks to my brilliant team in @BEISGovUK.

"I will continue from the back benches to work to ensure everyone is treated with dignity and respect," added the South Northamptonshire MP.

A clear sign that Mr Cox was on his way out was when he failed to appear at the Commons dispatch box for Attorney General Questions.

His place was taken by Michael Ellis, the Solicitor General, who fielded questions from MPs in his place.

Later, Mr Cox, said he had left Government at his request, saying: “I have been truly privileged to have served as Attorney General during the recent turbulent political times. I am now leaving the Government at the PM's request. I shall continue to represent and stand up strongly for the interests of Torridge and West Devon."

Ms Villiers said she was "sad" to have been removed from her post as Environment Secretary but in a lengthy Facebook post, noted: "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.”

Other sackings include Chis Skidmore as Universities Minister and Transport Ministers George Freeman and Nusrat Ghani.

With the sackings out of the way, Mr Johnson returned to Downing St to begin putting in place his new team. None of the main offices of state held by Sajid Javid as Chancellor, Dominic Raab as Foreign Secretary and Priti Patel as Home Secretary are expected to change.

Indeed, a smiling Mr Javid was the first to walk up Downing St.

Mr Raab greeted photographers on his way into No 10 but did not answer when asked whether he was confident he would be keeping his job. Ms Patel later arrived in Downing Street and did not say anything as she went through the famous black door.

READ MORE: Boris Johnson to make changes to government ranks

The pre-reshuffle trail was that there would be promotion for a new generation of female talent. Names in the frame for promotion include Anne-Marie Trevelyan, the Armed Forces Minister, Suella Braverman, the former Brexit Minister, and Gillian Keegan, the backbencher.

All eyes will be on what role Michael Gove, the Cabinet Office Minister and self-declared “Prime Ministerial gofer,” will get. There has been much speculation he will become the new COP26 President but it is thought he wants the Trade Secretaryship to lead the talks with the EU.

As ministers walked up Downing St a person outside the gates was using a large speaker to blast music towards them. Tracks included Fun Boy Three's The Lunatics [Have Taken Over the Asylum] and Part Of The Union by the Strawbs.