David Cameron reportedly told aides following his resignation speech: "Why should I do all the hard s**t?"
In the speech, the Prime Minister said he would continue in Number 10 until the party elects a successor, likely to be before the Tory conference in October.
Mr Cameron said: "It would not be right for me to be the captain that steers our country to its next destination.
"A negotiation with the European Union will need to begin under a new prime minister and I think it's right that this new prime minister takes the decision about when to trigger Article 50 and start the formal and legal process of leaving the EU."
When he went back inside Number 10, he explained to aides that he did not want to go through the tortuous process of beginning the UK's divorce from the EU and then resign.
"Why should I do all the hard s**t for someone else, just to hand it over to them on a plate?" he said.
According to Downing Street staff, Mr Cameron and his wife Samantha were greeted back in the office to standing ovation after which he thanked aides for their service.
A close aide to Mr Cameron told the Sun: "It was the moment it really sunk in for all of us that it was over.
“He went out with dignity, and that was the most important thing for us."
After Mr Cameron's speech, Boris Johnson, the leading contender to replace him, paid tribute to the Prime Minister's record, saying: "I have known David Cameron for a very long time, and I believe he has been one of the most extraordinary politicians of our age.
"A brave and principled man, who has given superb leadership of his party and his country for many years.
"It was his bravery that gave this country the first referendum on the European Union for 43 years."
David Cameron's premiership - in pictures
David Cameron's premiership - in pictures
Britain's Queen Elizabeth II greeting David Cameron at Buckingham Palace for an audience to invite him to be the next Prime Minister on 11 May 2010
Prime Minister David Cameron and his wife Samantha wave from the steps of Number 10 Downing Street on 11 May 2010
On 12 May 2010 Prime Minister David Cameron said in a press conference with Lib Dem leader Nick Clegg, who was then deputy PM, they plan to "take Britain in a historic new direction" and Conservative-led coalition government would be united and provide "strong and stable" leadership
A decade ago, David Cameron visited the Arctic to witness the effects of climate change. However since coming to power in 2010, his government has gradually dropped down a succession of green policies
Prime Minister David cameron told the then New York mayor Michael Bloomberg, the Queen had “purred down the line” after he told her Scotland had voted against independence in September 2014. He was forced to apologise for breaking constitutional convention
Britain's Prime Minister David Cameron greeted soldiers working on flood relief in York city centre after the river Ouse burst its banks, in northern England in December 2015
Claims that David Cameron performed an obscene act with a dead pig and smoked cannabis during his studies at Oxford University spread around the world in September 2015. The extraordinary allegations were made in an unauthorised biography of the Prime Minister written by Lord Ashcroft
David Hartley/REX Shutterstock
In 2016, Mr Cameron was caught up in a worldwide scandal dubbed the “Panama papers”
Prime minister David Cameron and his wife Samantha with seven week old Regan as they meet her parents, first time home buyers Robert Arron and Kelly Jeffers at the Heritage Brook housing development in Chorley, Lancashire. David Cameron has joked that he wants "another baby" and said that he feels a "bit broody" every time he sees a newborn on the campaign trail
Prime Minister David Cameron was criticised for branding refugees in the Calais ‘jungle’ camp as a “bunch of migrants” in January 2016 after thousands of refugees died in their attempt to cross the Mediterranean in 2015
Britain's Prime Minister David Cameron speaks with European Commission President Jean-Claude Juncker during an EU summit meeting on 17 March 2016 at the European Union council in Brussels. Cameron was in Brussels to renegotiate deal of UK membership with other European leaders. The deal, sealed after hours of haggling at a marathon summit, paved the way for a referendum on whether Britain will stay in the EU
President Barack Obama shakes hands with British Prime Minister David Cameron at a meeting at 10 Downing Street in London on 22 April 2016. The President and his wife visited 10 Downing Street where he joined press conference with British Prime Minister David Cameron and made his case for the UK to remain inside the European Union
After David returned from Brussels claiming victory in his renegotiation with European leaders, Boris Johnson announced that he will not support the Remain campaign. The prime minister said publicly he was "disappointed but Boris remains a friend"
Prime Minister David Cameron makes a joint appearance with Mayor of London Sadiq Khan as they launch the Britain Stronger in Europe guarantee card at Roehampton University on 20 May 2016 in London. The 'guarantee card' lists five pledges should Britain remain in the EU, including the protection of workers' rights, full access to the single market and stability for Britain
Britain's Prime Minister David Cameron speaks outside 10 Downing Street on 24 June 2016. Cameron announced his resignation after Britain voted to leave the European Union after a bitterly divisive referendum campaign
UKIP leader Nigel Farage tweeted after the announcement: "It's right that David Cameron has gone.
"Not a bad man just on the wrong side of the argument."
Downing Street have declined to comment.Reuse content