Theresa May set up a showdown between Parliament and judges yesterday as she vowed to cut the number of foreign prisoners who avoid deportation by pleading family commitments.
The Home Secretary wants MPs to set new guidelines on what the "right to a family life" enshrined in European law should mean in the case of a foreign criminal facing deportation, and indicated that she would change the law if the judges did not follow the Government's advice.
The move was part of plans aimed at reducing immigration, including a new income guarantee before migrants can bring their families into the country. Rights groups claim it will lead to thousands of families being broken up.
Mrs May originally promised a change in the foreign criminal rules at the Conservative annual conference last year, when she notoriously claimed that a Bolivian man had been allowed to stay in the UK because he had a pet cat. That claim was swiftly denied by the office representing senior judges.
Yesterday, Mrs May said there was no "absolute right" to a family life under the European Convention on Human Rights, denying that her position would put Britain on a collision course with the European court.
"There are some instances where the European court's actually been tougher than our own courts," she told the BBC's Andrew Marr Show. "The European court actually takes a tougher view on those who've built up so-called rights over a period of time when they've been here illegally.
"I would expect that judges will look at what parliament will say and that they will follow and take into account what parliament has said. If they don't, then we'll have to look at other measures and that could include primary legislation."
But she admitted yesterday that her headline-grabbing initiative on foreign prisoners was likely to have little impact on the overall immigration statistics. "This is not big numbers", she said, when compared with the effect of the Government's decision, announced last year, to cut the number of student visas issued each year by 52,000.
Labour's shadow home secretary, Yvette Cooper, said Mrs May should focus on sorting out the confusion at the UK Border Agency.
Jamie Beagent from the human rights team at the law firm Leigh Day & Co said: "It is hard to see what difference this guidance can make as it does not change the law and simply exhorts the courts to continue doing what they have been doing all along."
Mrs May will lay down new rules today preventing immigrants earning less than £18,600 a year from bringing their families into the UK.
The threshold is lower than originally planned, but the Joint Council for the Welfare of Immigrants warned that it would still mean nearly half of applications would be rejected and some 15,000 families would be forced to live apart. The council's Habib Rhaman said: "These measures are the actions of a vicious government."