British Immigration Minister Beverley Hughes resigned on yesterday after officials exposed lax controls allowing migrants from Romania and Bulgaria to enter the country with forged papers.

Prime Minister Tony Blair?s office said Hughes, 54, had quit for accidentally misleading parliament over the affair. ?It was clear that she had given a misleading impression to parliament, albeit unwittingly,? Blair?s spokesman told reporters.

Immigration is set to be a key issue at the next election, expected in the first half of next year, with Blair keen to counter opposition claims that his government is too liberal in allowing asylum seekers and new immigrants into Britain.

Hughes, who was elected to parliament in 1997 when Blair was swept to power, tendered her resignation on Wednesday night.

Blair accepted it on yesterday morning and Hughes is expected to make a statement to parliament later in the day. It was unclear whether she had jumped or was pushed although she received strong backing from her boss, Home Secretary David Blunkett, and Blair this week. Both described Hughes? job ? a minister of state position ? as the toughest outside the Cabinet of top government posts.

Blair?s government was plunged into a bitter row after a senior diplomat in Romania claimed that cases, some bogus, had been rushed through to clear backlogs in the system.

Blunkett has suspended all immigration applications from Romania and Bulgaria pending an investigation. His role will now also come under fire, although Blair?s spokesman said the premier thought he was a ?first class? minister. The diplomat who exposed the shortcomings, British Consul in Romania James Cameron, has been suspended.

The row follows a separate government inquiry into how checks came to be waived at an immigration centre in the northern city of Sheffield in order to clear a backlog there. That too was exposed by a whistleblower who was later suspended.

Opposition Conservative leader Michael Howard launched a scathing attack on Blair in parliament over the issue on Wednesday.

Hughes had said she was unaware of the situation but a year-old letter, to which she replied, from a fellow minister has now been discovered which detailed the problems in Romania and Bulgaria.

The Conservatives have published an e-mail from suspended diplomat Cameron, claiming that migrants were being let into Britain despite having forged papers.

They produced further e-mails between UK officials which showed the government knew more than a year ago about false claims from Romania and could not claim ignorance.