David Cameron has dismissed the prospect of a second EU referendum as he insisted voters backing a British exit would be the "final" decision.

The Prime Minister, in a thinly-veiled attack on London mayor Boris Johnson, told MPs that an approach to use a vote to Leave as a way of strengthening Britain's position in the EU ignores issues of democracy, diplomacy and legality.

He said a second renegotiation followed by a second referendum is "not on the ballot paper", adding: "For a Prime Minister to ignore the express will of the British people to leave the EU would not just be wrong, it'd be undemocratic."

Mr Cameron, making a statement in the Commons outlining his deal aimed at keeping Britain in the EU, said the country will continue to be great regardless of the choice made by voters.

He added: "I believe the choice is between being an even greater Britain inside a reformed EU or a great leap into the unknown.

"The challenges facing the west today are genuinely threatening. Putin's aggression in the east, Islamist extremism to the south - in my view, this is no time to divide the west.

"When faced with challenges to our way of life, our values and our freedoms, this is a time for strength in numbers."

Mr Cameron insisted he has "no other agenda than what's best for our country" as he reaffirmed he will not seek re-election.

He went on: "I'm standing here telling you what I think. My responsibility as Prime Minister is to speak plainly about what I believe is right for our country and that is what I'll do every day for the next four months."

Earlier, when outlining why there will be no second referendum, Mr Cameron joked he had not heard of couples seeking to renew their marriage vows by first seeking divorce.

Mr Cameron said: "On diplomacy, the idea that other European countries would be ready to start a second negotiation is for the birds.

"Many are under pressure for what they have already agreed.

"Then there is the legality and I want to spell out this point for the House carefully because it is important - if the British people vote to leave, there's only one way to bring that about and that is to trigger Article 50 of the treaties and begin the process of exit.

"And the British people would rightly expect that that should start straightaway."

Mr Cameron explained a two-year time period to negotiate Brexit would be triggered, noting it is not a process to rejoin but a "process for leaving".

He said: "Sadly I have known a number of couples who have begun divorce proceedings, but I do not know of any who have begun divorce proceedings in order to renew their marriage vows."

At this point, Labour MPs mocked and heckled Conservative MP Mr Johnson.

Mr Cameron warned Britain's access to the single market would cease immediately after the two-year period ended while trade agreements with 53 countries would lapse.

He said: "This cannot be described as anything other than risk uncertainty and a leap in the dark that could hurt working people in our country for years to come, and this is not some theoretical question - this is a real decision about people's lives.

"When it comes to people's jobs it's simply not enough to say it'll be all right on the night and we will work it out, and I believe in the weeks to come we need to properly face up to the economic consequences of a choice to leave."

Jeremy Corbyn said Labour was "overwhelmingly" for remaining in the EU because it provides jobs and protection for workers, investment, and action on the environment.

Describing the referendum as putting an "historic choice" to the British people, the Labour leader said: "We welcome the fact that it is now in the hands of the people of this country to decide that issue.

"The Labour Party and the trade union movement are overwhelmingly for staying in because we believe that the European Union has brought investment, jobs and protection for workers, consumers and environment and we are convinced that a vote to remain is in the best interests of the people."

But Mr Corbyn slammed Mr Cameron's renegotiated deal, claiming it does nothing to address the challenges facing Britain and instead amounts to a "theatrical sideshow" aimed at appeasing the Eurosceptic wing of the Conservatives.

He said: "In the 21st Century as a country and as a continent and indeed as a human race we face some challenging issues - how to tackle climate change, how to address the power of global corporations, how to ensure they pay fair taxes, how to tackle cyber crime and terrorism, how we trade fairly and protect jobs and pay in an era of globalisation, how we address the causes of the huge refugee movements across the world, how we adapt to a world where people of all countries move more frequently to live, work and retire.

"All of these issues are serious, pressing and self evidently can only be solved by international cooperation.

"The European Union will be a vital part of how we as a country meet those challenges, therefore it's more than disappointing that the Prime Minister's deal has failed to address a single one of those issues."

He added: "The reality is that this entire negotiation has not been about the challenges facing our continent, neither has it been about the issues facing the people of Britain, indeed it's been a theatrical sideshow about trying to appease, or failing to appease, half of the Prime Minister's own Conservative Party."

Mr Corbyn described the PM's deal as "largely irrelevant", saying it would have no impact on the case to remain in the EU.

But he welcomed moves to create a red card system for national parliaments and Britain's exemption from the EU principle of "ever closer union".

He agreed with an emergency brake on EU migrants' benefits but stressed that it does not address the issues of low pay, the undercutting of local wage rates, and the "grotesque" exploitation of migrant workers.

Mr Corbyn said it was right to reduce levels of child benefit paid out for children living outside the UK but also welcomed the protection for existing claimants until 2020.

Concluding, he said: "The Prime Minister's deal includes elements we welcome but others that concern us, but it's largely irrelevant to the choice facing the British people, not one single element has a significant impact on the case we are making to stay in."

Mr Cameron rejected Mr Corbyn's claims that the deal was all about the Conservative Party, claiming that leaders of Slovakia and Hungary and other significant European figures had welcomed the deal and the implications it has for the EU.

SNP Westminster leader Angus Robertson warned Mr Cameron that a vote to leave the EU would trigger a second Scottish independence referendum as the country overwhelmingly supports staying in.

He said: "Public opinion in Scotland by a majority supports membership of the European Union.

"Every single Scottish MP supports remaining in the EU as does almost every member of the Scottish Parliament and all bar one Scottish MEP.

"Do you have any idea what the consequences would be of Scotland being taken out of the EU against the wish of the Scottish electorate?

"I want Scotland and the rest of the UK to remain within the European Union.

"However, if we are forced out of the EU I am certain the public in Scotland will demand a referendum on Scottish independence and we will protect our place in Europe."

He also warned Mr Cameron against using so-called "project fear" tactics, which the SNP believes were used against it in the Scottish independence referendum in 2014, to scare voters into remaining in the EU.

Mr Cameron insisted he would make a positive case for remaining in the EU and insisted the vote was one for the whole of the UK.

Tory former cabinet minister Ken Clarke praised Mr Cameron's deal and attacked Leave campaigners.

He said: "It is not the politics of fear to point out that those who advocate a no vote don't seem to know what a no vote means.

"They continually imply that somehow all the benefits that flow from Europe in terms of jobs, investment, and security will somehow continue to come here when they have swept away the obligations that previous British governments have always accepted."

Leading Tory Eurosceptic Sir Bill Cash (Stone) asked Mr Cameron to clarify and "repudiate" comments he made referring to the apparent "illusion" of sovereignty which would be brought about by leaving the EU.

Mr Cameron said: "Let me confirm to you, yes, this parliament is sovereign.

"We have chosen to join the European Union, we could choose to leave the European Union.

"Let me explain exactly what I meant by saying there would be in many cases the illusion of sovereignty.

"Let me take one issue. We now have safeguards so that British banks, British businesses cannot be discriminated against.

"If we stay in the European Union they can't be discriminated against because we are not in the Euro.

"Were we to leave obviously we would not have that protection. They could discriminate against us frankly, I think they would discriminate against us.

"Therefore in that way we might feel more sovereign but it would be an illusion of sovereignty because we wouldn't have the power to protect the businesses that create jobs and livelihoods in our country."

Meanwhile, the former deputy Prime Minister Nick Clegg urged the UK to listen to its friends around the world on the issue.

He said: "President Obama has been crystal clear that if Britain were to leave the European Union it would weaken, not strengthen, the special relationship.

"The Indians, the Chinese are mystified that we are even risking exit from the European Union.

"Would you agree with me that if Britain in the future wants to stand tall in New Delhi, in Beijing, in Washington, in other global capitals, Britain must continue to stand tall in our own European neighbourhood?"

Mr Cameron replied: "I think you are right that we should make this decision ourselves as a sovereign nation and a sovereign people but I think it is worth listening to our friends and listening to what they think is best for our country.

"I have to say in all the leaders and politicians I have met around the world I can't think of any of our friends - not Australian, not New Zealand, not Canada, not America - who want us to leave the EU.

Mr Cameron said the only person who might want the UK to leave the EU is Vladimir Putin.

Ed Miliband, the former leader of the Labour party, stressed his belief that the UK has more influence inside the EU than outside it.

He said: "Of course by being a member of the European Union we don't always get our own way but as you said... on all of the major issues whether it's trade or climate change or terrorism and security, you can tell us because you have been the prime minister, do you believe we have more influence in the European Union or outside?

"Surely the answer is more influence inside the European Union, not outside.

"That's why I passionately believe we must remain in the European Union."

Mr Cameron agreed.

He said: "The big picture is this: When it comes to getting things done in the world that can help keep people safe in our country, a bigger, better deal on climate change, do we get more because we are in the EU?

"Yes."

Mr Cameron later said he believes the referendum will "settle the issue for a generation", adding: "We will be publishing the alternatives to membership so that people can see what they are and also people can see that there are plans that could be made."

Conservative former minister Peter Lilley told the PM: "For decades, British ministers who had involvement with Europe have attempted, and I include myself, to exaggerate the influence we bring to bear and conceal our inability to achieve British interests.

"Is that why it took a freedom of information request to establish that over the last two decades Britain has voted against 72 measures in the European Council and been defeated 72 times, and the pace of defeat is accelerating?

"If we make the mistake and take the risk of remaining in the EU, how many defeats do you expect in the next two decades?"

Mr Cameron said he did not underestimate the frustrations and challenges of being an EU member, but he said research he has seen suggests Britain achieves its position in 90% of cases - which outranks the Germans.

Mr Cameron claimed Britain needed to give up some sovereignty to join organisations like Nato or to sign international trade deals.

The PM insisted the question should be what maximises power and influence.

He was responding to Tory former minister Nick Herbert, who said: "Would you agree with me that when this country in our national interest makes an international agreement of any kind, it may involve a loss of sovereignty, that may be the case through any trade deal, through trading under WTO rules and indeed on the single most important issue that this House of Commons could take, which is whether or not to engage in military action?

"We are treaty-bound by Nato to go to the defence under Article 5 of a country, a fellow member, under armed attack and that obliges us.

"In that sense we have lost sovereignty because we believe it is in the interests of the country to enter into that agreement and has made us safer.

"If the claim of sovereignty and the loss of sovereignty were the trump card, would it not in fact be the case that all of those international agreements would have to be torn up?"

Mr Cameron replied: "I think you make a very good point.

"If your only determination was never to cede any technical sovereignty you would never join any of these organisations, nor would you do a trade deal nor would you probably be a member of the UN or the IMF or the World Bank.

"So therefore the question really is what maximises our power and influence and ability to get things done."

Tory founder of the Grassroots Out campaign Peter Bone hit out at Mr Cameron's warning against "linking arms" with the likes of Nigel Farage and George Galloway in the Leave campaign.

He said: "On Friday 2,500 people packed the QE2 centre to see GO launch the national cross-party Leave campaign.

"Amongst the speakers were two Ukip MEPs, a renowned economic commentator, a senior trade unionist, a very respected Labour MP, the co-chairman of Conservatives for Britain, four Conservative MPs and the leader of Respect.

"In 2014, Ruth Davidson, our excellent Conservative leader in Scotland, linked arms with George Galloway in the national interest (in the Scottish independence referendum).

"Do you agree that Ruth Davidson was right and do you agree that sometimes you have to work with people you don't like?"

Labour's Andrew Gwynne claimed Mr Johnson was warning against leaving the EU as little as 15 days ago.

The Denton and Reddish MP said: "I want to put a quote to you - 'leaving would cause at least some business uncertainty while embroiling the Government for several years in a fiddly process of negotiating new arrangements so diverting energy from the real problems of this country'.

"That was on February 7, the mayor of London was right 15 days ago, wasn't he?"

Tory outer Jacob Rees-Mogg (North East Somerset) could not resist a reference to Haribo sweets, which the PM reportedly used to boost his energy during last week's marathon Brussels talks.

He said: "May I congratulate you on spending 40 hours, apparently four clean shirts and a packet of Haribo in implementing the Labour Party manifesto in your conversations in Brussels?"

Labour MP Graham Stringer (Blackley and Broughton) accused the Prime Minister of suggesting that people who vote to leave the EU "don't love their country".

Mr Cameron rejected the claim.

"I absolutely did not say that," he said.

"What I said was that I love my country and I think our country, an amazing country, will be greater and more powerful if we remain in organisations through which we can project our power and influence and do great things in the world.

"I don't question the patriotism of anyone in our country. We are all going to have to make a choice."

Christopher Chope, the Tory MP for Christchurch, said Mr Cameron had previously suggested that if his negotiations had failed he would have recommended leaving the EU.

Mr Chope then asked Mr Cameron if he will publish the contingency plans for such an eventuality.

Mr Cameron said: "In terms of the documentation, we are going to be publishing something about the alternatives to demonstrate what we believe they are and to demonstrate that we are thinking about what would need to happen were that eventuality to come about."

Mr Cameron also faced questions on whether there could be a second referendum to ratify any potential treaty changes.

"The truth is it would depend what was in that treaty," he said.

Ian Paisley, the Democratic Unionist MP for North Antrim, asked Mr Cameron if the Northern Ireland Secretary Theresa Villiers should resign for coming out in favour of the UK leaving the EU.

Mr Cameron said: "The Secretary of State for Northern Ireland does an excellent job. She is exercising her ability to reach a personal decision and to campaign for Britain to leave the EU and that's absolutely right she is able to do that."

Tory former chancellor of the exchequer, Lord Lawson of Blaby, warned that Britain would end-up in a "quasi-colonial" relationship with Brussels if it voted to remain in the EU.

After the prime minister's statement was repeated in the upper house by the leader of the Lords, the former Cabinet minister dismissed David Cameron's achievements.

Lord Lawson branded the concessions negotiated by the prime minister as "trivial and inconsequential" changes.

"Is it not clear that the referendum we are going to have will not be about whether we wish to remain in a reformed European Union, it will be whether we wish to remain in an unreformed European Union?" the Tory peer said.

Lord Lawson said the rest of the EU was committed to full blooded political union which would have dire consequences for Britain.

"Maybe we won't be part of it, but we will still be shackled to it, and we will have something which is - the closest parallel is a quasi-colonial status," Lord Lawson said.

Tory former foreign secretary Lord Hague of Richmond said all possible alternatives to Britain remaining in the EU should be subject to intense scrutiny and analysis.

"There would be a basic choice between leaving the single market in order to escape its requirements, and its freedom of movement, and its regulations, or staying in the single market with those same requirements, and regulations, and would that not represent a loss of sovereignty rather than the recovery of sovereignty?" Lord Hague said.

Former leader of the Labour Party Lord Kinnock said voting to remain would be an act of "practicable patriotism" as he insisted it was "glib and duplicitous" to suggest voting to leave could compel the EU to strike a better deal with Britain.

"The choice is in or out, not in, out, shake it all about, and then rashly hope that something helpful will turn up for a country that has just abandoned all rights, all influence, all power by leaving the EU," Lord Kinnock said.

Former leader of UKIP Lord Pearson said the prime minister had secured a "pathetic deal".

Leader of the Lords, Baroness Stowell of Beeston, warned that Russian president Vladimir Putin would "cheer" if the UK left the EU, adding: "We don't want to do anything that is going to brighten his day."