David Blunkett should have made clear that he had a personal interest in the immigration application of his former lover’s nanny, it was claimed yesterday.

Sir John Gieve, the Home Office’s top civil servant, told the Commons public administration committee that even if the former home secretary had used the case to highlight concerns about immigration delays, he should have alerted officials to his interest.

He said: "Ministers have to be extremely careful they don’t mix the personal, political, the official."

Sir Alan Budd, the former Treasury official who conducted the official inquiry into the affair, added that he accepted that "people are very angry" that he had been unable to discover whether Blunkett raised the case simply to highlight wider delays or whether he had sought special help for her.