Cynical debate over immigration policies hides the real reason for border controls, says Alex Callinicos
It has become depressingly clear that the coming general election may be dominated by a degrading Dutch auction between Labour and the Conservatives, as each party strives to appear tougher on asylum-seekers than its rival.
Tory leader Michael Howard's announcement of his party's plans to impose health checks on immigrants suggests this particular debate will sink even deeper into the gutter.
Anyone familiar with Paul Foot's ground-breaking Race and Immigration in British Politics knows that these latest developments belong to a long-term pattern.
Racist agitation against newcomers to Britain, fuelled by rumour, anecdote and stereotype - sometimes manufactured and always amplified by the tabloid press - creates pressure to impose restrictions on immigration.
Ambitious and unscrupulous politicians jump on the bandwagon, while more centrist figures - in the past liberal Tories, now Labour ministers who retain some scruples from their anti-racist youth - impose controls in the belief that this will head off demands for more severe restrictions.
These concessions shift the political consensus on immigration further to the right, giving xenophobes a more favourable starting point from which to launch their next agitation.
An oddity about this infernal cycle - which is by no means exclusively British - is that it continues to spin against the background of an international convergence of economic policy that includes the abolition of all restrictions on the movement of capital around the world.
The International Monetary Fund and the World Bank demand that governments open their economies to foreign investors. Among the first significant policy changes that the Conservatives made in 1979 was to abolish exchange controls - after an election victory in which Margaret Thatcher made an appeal to anti-immigrant sentiment by referring to popular fears of being "swamped" by an "alien culture".
One of the paradoxes of the era of globalisation is that while capital is allowed to roam the world in search of profit, the international mobility of labour is becoming more constrained.
It is hard to make an economic case for these restrictions.
Even Labour ministers occasionally refer to evidence that shows that the inflow of immigrant labour brings a net benefit to the host economy.
This is not news to academics, who remember the immense intellectual fillip that American and British universities received thanks to the emigration of scholars from Nazi Germany.
Today, of course, the academy depends even more on the free movement of people and ideas. But the benefits are not confined to the most skilled forms of foreign labour.
I wonder if the ministers who propose to ban unskilled workers from outside the European Union have noticed that the workers in any central London park all seem to speak Arabic?
Great world cities such as London would cease to function if they were not constantly rejuvenated by the inflow of energy from the global South.
A cynic - or a Marxist - might offer the following explanation for the failure of free-market capitalism to give labour the freedom of movement it demands for capital.
There is enough misery in the world to provide people from the South with the incentive to evade northern immigration controls. But these restrictions make them illegal and therefore vulnerable once they have circumvented them.
So they are forced to accept low wages and worse working conditions than if they were legal. Immigration controls therefore fail to stop immigration, but they help big business get the foreign labour it needs on the cheap.
That's capitalism for you.
Alex Callinicos is professor of politics at York University.