David Cameron was told four years ago his immigration target was 'impossible' while Britain is in the EU – but continued to make the promise.

The claim is made today by the Prime Minister's ex-closest aide Steve Hilton, who attended the meetings with senior Whitehall officials in 2012.

He reveals Mr Cameron was warned 'directly and explicitly' by civil servants that his 'tens of thousands' net migration goal was not deliverable given EU freedom of movement rules.

Despite this, the Prime Minister has repeatedly restated his ambition to hit the target – even including it in his 2015 general election manifesto. At no stage has he succeeded in cutting net migration to below 100,000.

Mr Cameron denied the claims today and insisted that when Mr Hilton left government in 2012 immigration was falling and was close to the target.

David Cameron, pictured today with ITV's Lorraine, denied claims from his former close aide Steve Hilton that civil servants said getting immigration to the tens of thousands was impossible

Writing in today's Daily Mail, Mr Hilton recalls the warning to Mr Cameron, saying: 'We were told, directly and explicitly, that it was impossible for the Government to meet its immigration target as long as we remained members of the EU, which of course insists on the free movement of people within it.'

His comments amount to a charge that the Prime Minister has concealed from voters the inevitable failure of his flagship policy since early 2012.

Mr Cameron denied the charge today, telling ITV's Lorraine: 'It's simply not right. Actually when Steve Hilton left Downing Street in 2012, net immigration had actually fallen quite substantially and it got down to 154,000, so not far away from the ambition that I set.

'But look there are good ways of controlling immigration and my welfare break, saying that people who come and work here, have to work here for four years before they get full access to our welfare system, that's a good way, but pulling out of the single market, wrecking our economy, that is a bad way.'

During the referendum campaign, Mr Cameron has insisted it is still achievable, but he faced public anger over his failure to curb immigration on the BBC's Question Time on Sunday night.

Mr Hilton describes Britain's immigration system as 'broken' and says the target is 'simply not possible' while in the EU.

The policy guru, godfather to one of the Cameron children, also attacks Chancellor George Osborne and the 'political elite' – whom he accuses of 'playing with fire' by demonising the public's desire for control over our borders and destiny.

The Prime Minister's ex-closest aide Steve Hilton, pictured, who attended the meetings with senior Whitehall officials in 2012, said Cameron was warned against the target by civil servants

Mr Hilton writes that the immigration system is a 'social disaster because the decency and tolerance of the British people … are mocked when they see their local communities and public services overwhelmed by sudden and unplanned-for arrivals of people in large numbers'.

He adds that these 'dramatic changes … don't affect the neighbourhoods inhabited by our insular ruling elite'. It is also a political disaster, he writes, because 'when politicians make promises they cannot keep this erodes … faith in the democratic process'.

Mr Hilton says it is 'offensive' for Remain campaigners to argue Brexit supporters 'want a meaner, narrower Britain'.

Yesterday, as the clock ticked towards the historic vote:

Mr Osborne said redundancies could start as early as Friday in the event of Brexit;

Union boss Len McCluskey said the enlargement of the EU was a 'gigantic experiment' conducted at the expense of ordinary workers;

Labour leader Jeremy Corbyn said he is 'not a lover' of the EU;

A poll showed the contest is on a 'knife edge' - though financial markets rose amid speculation of a Remain win;

A senior figure in Britain Stronger in Europe was accused of trying to 'cynically' exploit the death of Labour MP Jo Cox.

Fears about illegal immigration via Calais, such as migrants trying to break into lorries pictured yesterday, have dominated the referendum campaign

The failure to cut immigration has been the PM's weak spot in the campaign.

The closest he came to his target was in 2012, when the figure for 12 months to September was 154,000.

But net migration in the 12 months to June 2015 was estimated to be 336,000.

Latest figures from the Office for National Statistics, covering 12 months to December 2015, estimate net migration to be 333,000. Just over half of this came from EU countries.

Despite this, Mr Cameron said on Sky TV earlier this month he did not 'accept' he would never meet his target, first set in 2010, adding: 'I think it remains the right ambition for Britain.' In February, he said he was 'convinced' it was still achievable.

Mr Hilton concludes: 'Undeliverable promises, an ungovernable country, an untrusted political establishment – this is what the EU has helped do to our country … time to leave.'

'The PM was told years ago we'd NEVER meet his migration targets while in the EU': Bombshell from friend and close aide who spent years at Cameron's side

By Steve Hilton

You may be surprised to read that I believe the Prime Minister has done everything in his power to control immigration. The problem is that as the leader of an EU member state, he doesn't have enough power to control immigration.

That goes to the heart not just of the migration debate, but of this entire referendum campaign and the decision we need to make as a nation in two days' time.

In all the years I worked as an adviser to David Cameron, he expressed a very clear point of view about immigration, one that I share. We believe that immigration has enriched this country's economy and society. As the son of immigrant parents, I feel this particularly strongly; I will forever be grateful to this country for the incredible opportunities it has given me.

Steve Hilton working with the Prime Minister in the Cabinet room of Number 10 Downing Street, when he was employed as an aide to David Cameron

And now, as an immigrant myself — to another country that prides itself on its open, inclusive character, the United States — I am doubly grateful for the fact that we live in a world where people can move freely and put down roots in places far from where they were born.

On many occasions, in public and private, I heard David Cameron set out his belief that precisely to protect this proud British heritage of welcoming people to our shores, immigration had to be controlled.

He spoke approvingly of the fact that in the Eighties, Margaret Thatcher's governments got the balance right on immigration, and that this contributed to the important and unequivocally positive fact that no party of the extreme Right ever managed to win significant support for a xenophobic anti-immigrant agenda.

He deplored the fact that subsequent Labour governments lost control of immigration, and was determined to get a grip. In office, I saw at first hand how seriously he took this responsibility. He had announced a clear commitment — to reduce the overall level of immigration to the tens of thousands annually — and understood very well that the public would rightly hold him to account for such a clear promise.

Immigration, alongside the threat of Islamic terrorism, was one of the policy areas that, in my observation, most occupied his time and focus. If anything, there were times when I wished he would focus more on other priorities; things that were perhaps closer to my heart.

But as the elected Prime Minister, he rightly got to call the shots.

Mr Hilton says the problem is that as the leader of an EU member state, Mr Cameron doesn't have enough power to control immigration

At the time, one of the main ways we assessed the success of our most important policies was through 'stock take' meetings. These involved ministers and civil servants responsible for a particular policy coming to No 10 for a long session, chaired by the Prime Minister, during which we could really get stuck into the details of how a particular reform was going.

I remember the meetings on immigration towards the end of my time in Downing Street. Everyone around the table, in some way or another, was working hard to try to deliver the government's commitment.

We were presented with analysis of the numbers of people coming to Britain through various routes, the impact of policy changes we had already made, and projections stretching into the future.

The news was not good. We were way off target; indeed, the numbers were going in the wrong direction. We explored various policy options — and I'm sure that process continued after I left the government in May 2012. But I recall very clearly one of the points that was made to us by the expert officials in the room.

We were told, directly and explicitly, that it was impossible for the government to meet its immigration target as long as we remained members of the EU, which, of course, insists on the free movement of people within it.

Mr Hilton says he remembers fighting endless battles with the Home Secretary Theresa May simply to get her agreement to the introduction of an Entrepreneur Visa

Now let me make one thing clear. The Remain campaign and its supporters say that leaving the EU will not on its own solve our immigration problems, and they are right about that. Leaving the EU is not a silver bullet. But, as we were advised in government, it is impossible for the 'tens of thousands' target to be met unless we leave — or negotiate an end to, or exception from, the free movement rules, which is an option Brussels has always refused to countenance.

In my view, the target itself is set at the wrong level. I would actually like to see more entrepreneurs, engineers, computer scientists — as well as those in genuine need of refuge — welcomed to Britain. I think that would help boost our economy and strengthen, not weaken, our society.

Others might take a different view: you could judge the Prime Minister's target to be about right. Or too high. That's what elections are for, to debate things like that.

But the point is, whatever the policy, whatever people vote for, it's not unreasonable to expect that the Prime Minister of the day is able to deliver it. That is simply not possible in the current, unreformed — and in my view unreformable — EU.

You don't need to sit in a 'stock take' meeting at No 10 Downing Street to see the obvious truth: our immigration system is completely broken, and as long as we're in the EU, our elected governments are powerless to fix it. Here are the ways in which this is a disaster.

It's an economic disaster because it means we have to clamp down on immigration that could benefit our economy (skilled labour) in favour of immigration from the EU that often doesn't (unskilled labour).

I remember fighting endless battles with the Home Secretary Theresa May simply to get her agreement to the introduction of an Entrepreneur Visa that would allow people from overseas with real potential to start their businesses here. It happened in the end, but only after massive internal opposition and watering down.

More broadly, almost every day in government we heard complaints about incredible individuals, whom we ought to have welcomed with a red carpet, being harassed and treated like second-class citizens by our immigration authorities.

Such people included Nobel Prize-winning scientists from Russia, some of our biggest investors from India, or even high-spending shoppers from China.

Our broken immigration system is a social disaster because the decency and tolerance of the British people, virtues that our politicians so love to talk about when it suits them, are mocked when they see their local communities and public services overwhelmed by sudden and unplanned-for arrivals of people in large numbers — the kind of dramatic changes which, needless to say, don't affect the neighbourhoods inhabited by our insular ruling elite.

Mr Hilton says that as Michael Gove and Boris Johnson have said, when politicians make promises they can't keep, it undermines not just faith in individual politicians but everybody's faith in the democratic process itself

And, of course, all this is a political disaster because, as Michael Gove and Boris Johnson have said, when politicians make promises they can't keep, it undermines not just faith in individual politicians but everybody's faith in the democratic process itself.

In the 2015 Conservative manifesto, the Prime Minister re-affirmed his commitment to the immigration target he had been told was undeliverable. When I saw that, I assumed this was either because he was certain he could negotiate a solution within the EU, or was assuming we would leave.

For the Government to continue to make the promise today, after no negotiated solution was achieved and while campaigning to stay, is, I think, what Gove and Johnson meant when they described this as corrosive of trust in politics.

There's a broader argument here, too, because the EU debate isn't just about immigration, which is why it is so offensive for the Remain campaign to argue, as George Osborne put it, that those like me who want to leave the EU 'want a meaner, narrower Britain'.

The fact is that with areas such as the economy, the environment, our legal system — which affect people's everyday lives in Britain — membership of the EU makes it impossible for the elected government to govern our country in the true sense of the word.

It seems to me that here in Britain, and especially in this referendum campaign, our insular ruling elite is playing with fire.

By dismissing — or worse, demonising — people's desire for control over the things that matter to them, and their perfectly reasonable expectation that the government they elect should have the power to deliver its promises, the rulers are the ones stoking the anger they decry.