From this:

Immigration will add six million to Britain's population over the next three decades, according to new figures. The estimate, by the think tank Migrationwatch UK, is based on the latest forecasts from the Government Actuary's Department (GAD).

They appear to confirm claims made by Migrationwatch two years ago, when the group first sprang to prominence by calling for a debate on immigration.

It was accused of scaremongering and ministers cast doubt on the accuracy of its figures...

Migrationwatch's research has opened up the debate on immigration for the first time since the late 1960s. The huge increase over the past five years has forced the big political parties to address the consequences of a rising population.

Opinion polls show that immigration has emerged as the voters' biggest concern, and Migrationwatch accuses other pressure groups of deliberately wanting to withhold the true facts from the public.

Internal Home Office memos obtained by Migrationwatch using data access laws have shown how Whitehall officials objected to the way the organisation's research was being traduced. One e-mail said: "Can we stop saying that Migrationwatch forecasts are wrong . . . Migrationwatch assumptions are often below the Government Actuary's Department high migration variant."

Sir Andrew Green, the chairman of the group, said: "The Government should explain why they have stimulated massive levels of immigration without consulting the British people and how and when they propose to bring it to an end."