Why did immigration to Britain increase so rapidly in recent years? David Goodhart, editor of Prospect magazine, considers the question for Radio 4's Analysis programme.
Eastern European fruit pickers have benefited from UK immigration laws
Since Labour came to power in 1997, Britain has experienced what is comfortably its largest wave of immigration ever. Yet it seems to have happened almost by accident.
At no point in the last 12 years does there seem to have been a general discussion in cabinet about the country's immigration strategy.
I have discovered that the final decision to open Britain's labour market to Eastern and Central Europeans was taken by a small group of officials and special advisers before an EU Council of Ministers meeting in Brussels.
It is emblematic of the insouciant way in which the great demographic transformation has occurred.
An accumulation of small decisions, all of them perfectly rational and sensible in their own right, has led to a mighty big - and pretty unpopular - outcome.
Churn and flow
There are two aspects to immigration.
There was never enough preparation, especially for the big East European inflow and the pressure on public services
There is the churn of people coming in for a few years, usually to study or to work and then returning home. And there is the flow of people gaining permanent right of residence.
The churn since 1997 has been enormous, rising from net migration of just a few tens of thousands in the early 1990s to routinely above 200,000 in the past decade. Those are far bigger numbers than ever before, with a total inflow in just 12 years of 5.4m foreign citizens coming for at least one year.
Meanwhile, 1.6m people have been granted permanent right of residence in that time - mainly from developing countries. In 2008, 24 per cent of all births in England and Wales were to foreign-born mothers, rising to nearly 50 per cent in London.
Notwithstanding some recent falls as a result of the recession, we may now be on a permanently higher immigration plateau.
So why did it happen? I did not want to rehearse the old arguments for and against mass immigration. Rather I wanted to try to disentangle the reasons it happened at all.
There were two big background factors: cheaper mass transit and the pull of Britain as a magnet both economic and cultural.
LISTEN TO THE PROGRAMME
BBC Radio 4, Monday 8 February at 2030 and repeated Sunday 14 February at 2130 GMT
A fast growing British economy - at least for most of the last 12 years - plus a deregulated labour market meant jobs galore.
Then there is the pull of the English language and of London - a global city with existing communities from all around the world.
What is more, between 1997 and 2003 there were, I think, five significant government decisions.
First, there was the abolition of the primary purpose rule, very unpopular with South Asians in particular, the repeal of which did have the effect of significantly raising the inward flow of spouses.
Second, there was the introduction of the Human Rights Act, which among many other things made it harder to restrict the number of asylum seekers.
Third, there was a liberalisation of student visas which more than doubled to over 130,000 a year. The government has just announced plans to restrict abuse of the system.
Fourth, there was a similar liberalization of work permits.
Fifth, opening the British labour market to people from the new EU states, seven years before any other big EU member. Instead of a few tens of thousands, more than 1 million people came after 2004.
The bureaucratic mess that the government inherited in 1997, especially over asylum, was another factor pushing up the numbers.
All of these, with the exception of the primary purpose rule, had powerful non-immigration rationales too.
The government has promised tougher rules to stop abuse of student visas
Attracting foreign students helped pay for a growing higher education system.
An expansion of work permits was vital to recruit nurses and doctors from abroad for the NHS. And Britain felt a responsibility to stick by its "New European" allies - many of whom had backed it over Iraq.
There were powerful pro-immigration lobbies at work too.
The situation demonstrates the thesis that a view held weakly by many people will, even in a democracy, always be trumped by a view held strongly by a small number of people, especially if the latter have access to power.
Large majorities of people tell pollsters that they are hostile to mass immigration. But business lobbied very effectively for liberalisation. Whitehall was mainly in favour. And there was a network of NGOs and legal campaigners who pushed to keep the door as wide as possible.
A large part of the metropolitan middle class was not only comfortable with an increasingly multi-racial Britain but also benefited economically from the cheaper labour.
'Absence of mind'
Notwithstanding what I said earlier about the apparently careless manner in which historic decisions have been taken, it would be wrong to say that in this area things were made up on the hoof.
There have been six major Acts of Parliament relating to asylum and immigration since 1997. Tony Blair spent a huge amount of time on asylum when popular anxiety was at its peak.
I have spoken to several officials and advisers involved who now admit that immigration policy in the late 1990s was unbalanced.
There was never enough preparation, especially for the big East European inflow and the pressure on public services. The downward pressure on wages for poorer Britons was not factored in properly - let alone the less tangible cultural effects in places like the East of England.
And, belatedly, the government has put in place an immigration system that at least gives the country more potential control.
But when historians come to look back on this period in 100 years time they will surely conclude that, as John Seeley said about the expansion of the British Empire, we acquired a whole new population in a "fit of absence of mind".
David Goodhart explores immigration for BBC Radio 4's
programme on Monday 8 February at 2030 and Sunday 14 February at 2130 GMT. Or listen again via the
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