David Cameron cracked jokes today as he faced MPs for the first time since his humiliation in the EU referendum - but Boris Johnson was nowhere to be seen.

The Prime Minister seemed demob happy as he appeared in the Commons, quipping that he thought he was having a 'bad day' until he realised the scale of the Labour coup against Jeremy Corbyn.

He also urged the newly-elected Tooting MP took keep her mobile phone on as she 'might be in the shadow cabinet by the end of the day'.

David Cameron cracked jokes today as he faced MPs for the first time since his humiliation in the EU referendum, laughing as he quipped that the coup against Corbyn put his bad day into perspective

Mr Cameron joked that he thought he was having a bad day until he saw the scale of the coup against Jeremy Corbyn (pictured)

The strongest contender to replace Cameron as leader is Boris Johnson, but he was nowhere to be seen in the Commons this afternoon, with SNP MPs shouting 'Where's Boris?' as the session began

But Mr Cameron was defiant about his controversial 'Project Fear' warnings about the consequences of Brexit, saying we were already seeing the fallout from the decision.

And he hit out at 'despicable' racist incidents in the wake of the referendum Leave vote, saying they 'will not stand for hate crime'.

The appearance came as it emerged that Mr Cameron's successor as Prime Minister will be appointed by September 2 at the latest.

The winner of the Conservative leadership contest will be announced on that date, with David Cameron potentially handing over the keys to Downing Street the same day.

The party's powerful 1922 committee has set out the timetable for the contest to succeed Mr Cameron, who had previously suggested a successor should be in place by October.

Nominations for leader will open on Wednesday, and close the following lunchtime. If there are more than two candidates, MPs will vote to whittle the field down next week, before Tory activists decide the final winner.

The favourite to win the top job, Boris Johnson, declared 'that Project Fear is over' this morning as he sought to reassure Britain that pensions were safe, the pound and markets were stable and told the nation: 'That's all very good news'.

Earlier that day, as Labour leader Corbyn left his Islington home, he had had to wrestle his way through an an army of reporters asking why he is holding on as more than half of his Shadow Cabinet resigned

Former Shadow Leader of the House of Commons Chris Bryant (left), and former Shadow Business Secretary and First Secretary of State Angela Eagle have all resigned from Corbyn's Cabinet, mounting pressure on him

But he was nowhere to be seen in the Commons this afternoon, with SNP MPs shouting 'Where's Boris?' as the session began.

Mr Cameron said: 'The British people have voted to leave the European Union. It was not the result I wanted – nor the outcome that I believed is best for the country I love. But 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 have already seen that there are going to be adjustments within our economy, complex constitutional issues, and a challenging new negotiation to undertake with Europe.

'But 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.

Mr Cameron reaffirmed that it would be for his successor when to trigger Article 50 under the Lisbon treaty.

Some EU figures, including European Commission president Jean-Claude Juncker, have called for an immediate start to the talks.

But Mr Cameron told the House: 'Before we do that we need to determine the kind of relationship we want with the EU and that is rightly something for the next prime minister and their cabinet to decide.

'This is our sovereign decision and it will be for Britain and Britain alone to take.'

George Osborne looked exhausted and rubbed his eyes as he sat alongside the PM during his statement

He suggested that the UK should be looking to stay in the single market, stressing it was important that Britain maintained the 'strongest possible' economic links with the EU as well as its extensive security co-operation.

'Britain is leaving the European Union, but we must not turn our back on Europe or the rest of the world,' he said.

'I believe we should hold fast to a vision of Britain that wants to be respected abroad, tolerant at home, engaged in the world and working with our international partners to advance the prosperity and security of our nation for generations to come.'

The PM strongly condemned abuse of members of ethnic communities reported after last week's vote as well as 'despicable' graffiti daubed on a Polish community centre.

'Let's remember these people have come here and made a wonderful contribution to our country. And we will not stand for hate crime or these kinds of attacks. They must be stamped out,' he said.

Mr Cameron refused to rule out the possibility of a snap general election. His former Liberal Democrat deputy Nick Clegg pointed out that the Conservative Party membership made up 0.003% of the total electorate, but would be responsible 'Do you agree with me that there should be an early general election?'

Chancellor George Osborne announced earlier that there will be no emergency austerity budget as he talked at The Treasury, where he moved to try to calm market turmoil triggered by the Brexit vote

Boris Johnson (pictured outside his north London home) heaped praise on the Chancellor for calming the markets, declaring 'Project Fear is over'

Mr Cameron said he stood by his Project Fear warnings during the campaign, arguing that we are already seeing the fallout from the vote

Mr Cameron replied: 'All parties have their rules for electing leaders that are arrived at democratically, we have ours and they will be followed.

'The only other point I'd make is that in the coalition agreement, we agreed a Fixed Term Parliament Act, which many of my colleagues have misgivings about.

'I happen to think it is a good measure, so as a result I think the right thing is for a new prime minister to take office and it will be for them to decide whether to fulfil the terms of this parliament or something else.'

The PM insisted pro EU ministers could not join the campaign for a second referendum or try to block Brexit.

Mr Cameron said that collective responsibility, which had been suspended to allow Cabinet members to campaign on both sides of the argument in the EU referendum, is now back in force.

He told the House of Commons ministers are now united in 'one view' - to get the best possible deal for the UK following the decision to sever ties with Brussels.

He told a packed House of Commons: 'On collective responsibility I meant what I said, obviously it was suspended for the period of this campaign but it has come back into place so members of Government, members of the Cabinet, are of one view.

'And that one view must be that we deliver the country's will to exit the European Union, although the key decisions for that will be taken by the next Prime Minister.'

CHOOSING A PM: HOW THE CONSERVATIVE LEADERSHIP ELECTION WORKS David Cameron announced he is resigning as Prime Minister when he made his post-Brexit statement in the early hours of Friday morning alongside his wife Samantha The leadership election is a two-stage process - first Conservative MPs have their say, then members of the party all around the country are able to vote. If there are two or more candidates, all Tory MPs vote on who they prefer, with the bottom candidate in each round being eliminated until only two are left. The final two then make their pitch to members of the party in a straight head-to-head contest, with the winner determined by postal voting. The exact timescale is unclear, but David Cameron said today that he wants his successor in place by the time of the party conference in October, meaning that the process will have to begin within weeks. Only full members of the party who pay their £25 subscription are entitled to vote - unlike in Labour's leadership contest, where supporters could register for just £3. Advertisement

The PM reiterated his position that the Government must 'accept the result' the British people had given and 'get on and deliver it'.

He added: 'I think people won't be surprised to hear that I'm not planning a second referendum.'

Mr Cameron raised a laugh from MPs when he pointed out that Mr Johnson, MP for Uxbridge and South Ruislip, was not bound by the rules of collective responsibility.

When he was praised for his performances at the despatch box, Mr Cameron joked that he would miss the three-hour marathon Commons sessions after statements.

'I wonder what I will do with my time,' he said wryly.

Earlier, Mr Johnson struck a notably conciliatory tone as he heaped praised on George Osborne for his 'reassuring' statement to calm the markets this morning and his decision to cancel plans for an emergency budget.

Mr Johnson spoke outside his north London home this morning after effectively launching his leadership bid by appealing to pro-EU supporters in his party and the wider public.

He softened his tone by rowing back on several key arguments he made in favour of Brexit before the EU referendum and hopes it will persuade Mr Osborne to back his leadership campaign.

The Chancellor, who made an early morning statement to calm the markets before they opened at 8am, is set to play a decisive role in the upcoming Tory contest to replace David Cameron.

Mr Johnson has reportedly offered him the job of Foreign Secretary if he supports his campaign as he is desperate to fend off a tough challenge from Theresa May, the Home Secretary.

Some Tories determined to block Mr Johnson think a crowded field is the best way of keeping him out of the final two names, with grassroots members choosing the winner. Those planning to run include:

Pro-Remain MPs Sajid Javid, the Business Secretary, Education Secretary Nicky Morgan, Work and Pensions Secretary Stephen Crabb and Energy and Climate Secretary Amber Rudd

Prominent Brexit campaigners Andrea Leadsom, minister for energy and climate change, and work and pensions minister Priti Patel

The details emerged as Mr Cameron set up a new government 'Brexit unit' amid calls for Michael Gove to be put in charge of negotiating a new deal.

The team, including officials from the Treasury and Foreign Office, will lay the ground ahead of real negotiations that will kick off when a new Prime Minister takes office in October.

But it will not make any firm decisions about what will happen.

A Downing Street spokeswoman said: 'What the civil service is there to do is to make sure that we prepare, as much as the civil service can, for a new prime minister.'

Cabinet Office minister Oliver Letwin, Mr Cameron's long-standing troubleshooter, will also be given a new 'facilitative role', consulting across government.

Theresa May (pictured left arriving at today's Cabinet meeting) Boris Johnson (pictured right as he left his home today) are battling each other to win over George Osborne (pictured middle as he arrived to deliver a pre-markets speech this morning), who is set to play a decisive role in who wins the leadership contest