David Cameron today blasted leave campaigners such as Boris Johnson who suggest job losses or a 'dent to the economy' are a price worth paying for Brexit.

The London Mayor last week conceded there 'might' be a blow to the economy following a Leave vote but at a speech today Mr Cameron said there was 'nothing more important than protecting people's financial security'.

Brexit campaigners issued their own research today which claimed the EU was costing jobs and insisting Britain was better off out.

David Cameron, pictured speaking at a Vauxhall factory today, warned Brexit would cost jobs and raise mortgage rates and insisted this was not a price worth paying

Speaking at the Vauxhall factory in Ellesmere Port, Mr Cameron said: 'For those who advocate leaving, lost jobs and a dented economy might be collateral damage, or a price worth paying.

'For me, they're not. They never are. Because there's nothing more important that protecting people's financial security.'

The Prime Minister repeated his claim that Britain would be a 'great country' outside of the EU.

But he warned: 'The question is: where will our economy be stronger; where will our children have more opportunities; where will families have the most security; where will Britain be better off: in or out of a reformed Europe?'

Mr Cameron claimed to be making the positive case for the single market, insisting tariff-free trade was a vital benefit to Britain.

He warned Britain would face a string of new tariffs on its exports if it quit the single market and said the Brexit camp could not be certain about when or in what form new deals would be struck.

The Prime Minister said: 'The best free trade deal in the world would still not replicate the single market.'

The case was rejected today by Vote Leave as Commons leader Chris Grayling insisted the Government's claim of a 'special status' for Britain meant little.

He said: 'If we vote to stay in the EU, we are voting to be substantially and increasingly governed from Brussels.

'It would be a vote for an unreformed EU which will hoover up more money and more power at every opportunity it gets.

'A vote to remain is a vote to leave the EU court and unelected EU judges in control of a whole raft of our laws.'

Mr Cameron met workers at the factory before making his latest intervention on the Brexit campaign

Mr Cameron's latest speech on the EU referendum campaign took him to Ellesmere Port as he spoke to Vauxhall workers about the benefits of membership

Mr Grayling insisted the Prime Minister had made a 'herculean' effort in Brussels but the lack of reform on offer underlined why Brexit was necessary.

And he warned the EU was 'on a journey' to greater integration Britain should avoid.

He said: 'In the early days all member states had a veto over new laws. So we had plenty of opportunities to protect our national interest.

'But the EU today has moved a long way away from those roots. Treaty after treaty scrapped those vetoes and made an increasing proportion of new EU legislation subject to qualified majority voting, leaving us unable to stop things that we did not agree with.

Mr Cameron's remarks appeared aimed at Boris Johnson, left in Downing Street this week, who said Brexit 'might' cost jobs but the case was dismissed today by Chris Grayling, right

'More and more areas of policy have fallen under the control of Brussels.

'And that's the first big problem that does not change as a result of the latest agreement.'

In other campaign developments today, the date of the Queen's speech was confirmed as May 18.

Commons leader Mr Grayling announced the date to MPs following speculation the set piece of constitutional theatre would be delayed until after the EU referendum campaign.

Unite leader Len McCluskey last night blasted German leadership of the EU in a speech at the German embassy.

He said he would be voting to Remain on June 23 but demanded further reforms to the organisation.

Amid concern the EU referendum has become too dominant, Mr Cameron has reportedly abandoned plans to hold the Queen's Speech, pictured last year, after the referendum rather than its usual slot in May

Mr McCluskey said: 'But the Greek crisis last year showed a very different and less attractive face of Europe. The threat of 'Grexit', the imposition of punishing austerity and the effective subjugation of the national democratic will, showed the EU and Germany's leadership of it in a very unattractive light indeed.

'What principle is being upheld when Greece's health service is pushed into ruin, when a generation is reduced to beggary in order to ensure that banks – yes, British as well as German – are repaid on time? It certainly isn't solidarity.

'Greece may have, indeed, been in financial crisis due to its own political leadership – but as journalist Paul Mason has said ''It may [have been] at the bottom of the economic pecking order, but Europe was supposed to be more than [just] an economy''.'

Speaking to the BBC last week, Mr Johnson admitted there could be an economic shock after a Brexit vote - but insisted this 'might not' be the case.

He said: 'Actually, there are plenty of people who now think the cost of getting out would be virtually nil and the cost of staying in would be very high.'

Unite boss Len McCluskey has attacked German leadership of the European Union, insisting the drive for austerity turned a generation of Greeks to 'beggary'

If Britain backs Brexit we'll face 13 per cent tariffs on SOCKS claims David Cameron in his latest warnings on the referendum

Mr Cameron, pictured during his speech today, said British businesses would face higher costs outside the EU

Britain could face spiralling tariffs on everything from socks and gloves to cars and bicycles if it quits the EU, David Cameron warned today.

The Prime Minister said before Britain joined the single market it faced a dizzying array of different tariffs on different products.

He warned no trade deal with the single market would ever be as comprehensive as being a member of the group.

In a speech to care workers in Cheshire, Mr Cameron said: 'Before we joined, we faced extremely high tariffs - 14 per cent on cars, 17 per cent on bicycles, 32 per cent on salt, 37 per cent on china.

'Even oddly 20 per cent on gloves but only 13 per cent on socks.

'All this meant higher costs for businesses and for consumers and less choice on supermarket shelves.

'Today there is one tariff in the single market and it is 0 per cent.

'What it means is this: a British businesswoman can sell her goods in Berlin as easily as she can in Birmingham. A lorry that sets off from Sunderland doesn't have to deal with layers of bureaucracy in every country as it heads, for instance, to Salzburg.'

Matthew Elliott, Chief Executive of Vote Leave said: 'After we vote leave, Britain will carry on being part of the free trade zone that stretches from Iceland to Turkey.

'We’ll also be able to take back control of immigration and spend our money on our priorities like the NHS.