Pressure was growing on British Prime Minister Boris Johnson on Friday to act more quickly and leave office faster than his planned exit in October.
Some Conservative MPs want him to leave office before a new Tory leader and prime minister is elected.
And opposition leader Sir Keir Starmer has said Labour would use a House of Commons motion to try to remove Mr Johnson if he refuses to hand over the reins to a caretaker other than himself.
Mr Johnson, who wants to stay in office for three months while the next party leader and prime minister is elected, has promised to not make major policy changes or fiscal decisions while in the caretaker role.
He chaired a meeting of his new Cabinet at Number 10 Downing Street hours after announcing his resignation as Conservative Party leader.
Starting his tenure as caretaker prime minister until a replacement is found, Mr Johnson welcomed his reshuffled team to the Cabinet Office on Thursday afternoon to set out his agenda.
“I want you to know that from now until my successor is in place, your interests will be served and the government of the country will be carried on," he said in a later tweet.
After 59 resignations from his government, including two Cabinet ministers, he appointed new figures to replace the disaffected MPs.
'Unwise' for Johnson to remain in No 10
Former Tory leader Sir John Major warned it was “unwise” for Mr Johnson to remain in office until a successor is chosen.
Sir John called on the powerful 1992 Committee of backbench Tory MPs to appoint an acting prime minister or streamline the election process to elect a new leader “solely by MPs”, and not by all party members.
“The proposal for the prime minister to remain in office for up to three months, having lost the support of his Cabinet, his government and his parliamentary party, is unwise and may be unsustainable,” he wrote in his letter to Sir Graham Brady, chairman of the 1992 Committee.
“For the overall wellbeing of the country, Mr Johnson should not remain in Downing Street — when he is unable to command the confidence of the House of Commons — for any longer than necessary to effect the smooth transition of government.”
Andrew Bridgen, the Conservative MP for North West Leicestershire, said he spoke to Sir Graham and urged him to shorten the process to replace Mr Johnson.
"I think we will have two candidates out of the parliamentary party to present the membership before recess," Mr Bridgen said. "And that will be no more than three or four weeks.
"So by the end of August we will have a new leader of the Conservative Party. So Boris Johnson's estimate that he'll still be Prime Minister in October is wildly inaccurate."
Sir Ed Davey, leader of the Liberal Democrats, said it would be “ludicrous” for Mr Johnson to stay on until a new leader has been chosen by the Conservatives, and added his voice to growing calls for a change of government.
“Johnson may have gone but the stain on the Conservative Party can't be removed that easily,” Sir Ed tweeted. “This cruel, callous government must go.”
Who is in Boris Johnson’s new Cabinet?
Nadhim Zahawi, Chancellor
The Iraqi-born MP was promoted from education secretary to Chancellor after Rishi Sunak quit on Tuesday.
Mr Zahawi now holds the second most powerful office in the UK and is expected to be one of the runners in the Conservative leadership race.
On Thursday, just a day after the prime minister handed him the top job, Mr Zahawi publicly called on Mr Johnson to step down.
Steven Barclay, Health Secretary
Mr Johnson on Wednesday appointed Steve Barclay Health Secretary after Sajid Javid’s resignation on Tuesday evening, which prompted the floodgates to open.
Shailesh Vara, Northern Ireland Secretary
The MP who was born in Uganda to Indian parents replaces Brandon Lewis, who stepped down on Wednesday.
Kit Malthouse, Chancellor of the Duchy of Lancaster
The former policing minister becomes the most senior minister in the Cabinet Office after the prime minister. He succeeds Mr Barclay.
James Cleverly, Education Secretary
The post was left vacant after Mr Zahawi was promoted to chancellor. Michelle Donelan was appointed education secretary on Wednesday before quitting on Thursday.
Mr Cleverly previously served as chairman of the Conservative Party and minister of state for the Middle East and North Africa, and North America.
Over the past few months he served as minister for Europe and North America.
Sir Robert Buckland, Wales Secretary
He replaces Simon Hart, who in stepping down told Mr Johnson that there was “no other option left” and his efforts to turn his government in the right direction had “passed the point where this is possible”.
Sir Robert suggested the new Cabinet would not get much done during the “caretaker period” and said it was “crucial” for there to be enough people carrying out the functions of government amid the wait for a new leader.
He said Mr Johnson would have limited scope to introduce fresh policies in the weeks ahead, but defended his decision to take a position in the new-look caretaker Cabinet, stressing he felt the need to “help and serve”.
Sir Robert, a former Lord Chancellor, accepted the offer of a Cabinet post just hours after questioning Mr Johnson’s integrity and saying he “can no longer go on”.
Greg Clark, Levelling Up Secretary
The appointment came after Mr Johnson sacked Michael Gove on Wednesday after asking him to resign.
Mr Clark, a former business secretary, went on the record to say he had voted to remove Mr Johnson in the no-confidence vote last month, which the prime minister passed but lost the support of 41 per cent of his MPs.
Shortly after his appointment, Mr Clark tweeted: “We have a duty to ensure that the country has a functioning government in the weeks ahead.
“Having been secretary of state at the communities department before, I will do my best to provide stability, good governance and accountability to Parliament at this important time.”
He served in the Cabinet under Theresa May, and David Cameron as communities secretary and then business secretary.
Mr Clark's appointment suggested Mr Johnson was reaching out to different wings of the Tory party.
Adam Stephenson, minister without portfolio who will attend Cabinet
“I have loyally supported our last three prime ministers and our party in delivering for our country," Mr Stephenson tweeted.
"Now that Boris Johnson has decided to resign we must ensure a smooth transition so we may continue to do so."
Mr Stephenson previously served as a minister of state at the Department for Transport and a minister in the Foreign Office.
Liz Truss, Foreign Secretary
Ms Truss, who is tipped to compete in the Tory leadership contest, keeps her position as Foreign Secretary after remaining loyal to Mr Johnson.
After he announced his resignation, Ms Truss tweeted: “The PM has made the right decision. The government under Boris's leadership had many achievements — delivering Brexit, vaccines and backing Ukraine.
"We need calmness and unity now and to keep governing while a new leader is found.”
Suella Braverman, Attorney General
Her role did not change in the reshuffle.
Ben Wallace, Defence Secretary
Mr Wallace remains in his post, saying he and a number of others “have an obligation to keep this country safe, no matter who is PM”.
Grant Shapps, Transport Secretary
Mr Shapps remains in his role.
Priti Patel, Home Secretary
There was no change for Ms Patel, a long-time ally of the prime minister.
Nadine Dorries, Culture Secretary
Ms Dorries retains her portfolio.