The result of the European Union referendum must be respected, David Cameron has said.
The Prime Minister made the comments at his first parliamentary statement since losing the plebiscite.
Mr Cameron however reiterated his call for Brexit itself not to start until his successor is put in place following his resignation.
"There can be no doubt about the result. Of course I don’t take back what I said about the risks, it is going to be difficult, we've already seen that there are going to be adjustemnets in our economy and challenging constitutional issues" he told MPs.
"I am clear and the Cabinet agreed this morning that the decision must be accepted and the process of implementing the decision in the best possible way must now begin."
Boris Johnson – Mr Cameron's adversary during the European Union referendum and the favourite to succeed him – was nowhere to be seen during the statement in the otherwise packed House of Commons.
His colleague Michael Gove, the Justice Secretary, also appeared to be absent.
Some MPs, including Labour MP for Tottenham David Lammy, have said Brexit could potentially be stopped despite the referendum result, which is only advisory.
The Liberal Democrats have said they will keep Britain in the EU if they win the next general election, which could be sooner than 2020 if a snap vote is called after a new Prime Minister is elected.
A petition to hold a second vote on keeping Britain in has also gained nearly four million signatures.
Leave-backers could face some obstacles despite their victory: Parliament is thought to have a majority in favour of remaining in the EU and it is believed that an Article 50 vote to trigger secession would requite a parliamentary vote. This means MPs could potentially derail plans.
The PM also called for the country to unite in the wake of the divisive referendum campaign, branding recent reports of a rise in hate crimes against EU migrants in the wake of the vote "desipcable".
The impending end of the PM's career in frontline politics did not seem to dampen his spirits; he made a gag suggesting that the new Labour MP for Tooting who entered parliament through a by-election earlier this month should keep her mobile phone on in case she was invited to join the shadow cabinet.
The joke was a reference to the troubles of Labour leader Jeremy Corbyn, who is facing a rebellion from his own MPs. Mr Cameron added: "I thought I was having a bad day.!"
Mr Cameron announced that he would step down the morning after it became clear Britain was leaving the EU.
He said his successor should be in place by Conservative party conference in early October, though backbench MPs have called for the competition to take place earlier
The PM backed the Remain side, which lost the vote by 48 per cent to 52 per cent. The policy of calling the referendum was included in his 2015 general election manifesto.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies