DOMINIC Grieve continues to be a vocal figure in the government’s proposed changes to anti-terror laws dealing with Britons travelling overseas to fight in Iraq and Syria.

David Cameron this week announced new measures designed to give police and officials more powers to sieze passports of suspected jihadists and stop them returning to the UK.

But Beaconsfield MP Mr Grieve, who slammed Boris Johnson’s initial call for stronger terrorism powers, has warned the Prime Minister that the changes could be illegal under UK and international law.

He said in Parliament: "I do share concerns that have been expressed that the suggestion British nationals, however horribly they may be alleged to have behaved, should be prevented from returning to this country.

"Not only does it offend principles of international law, it would actually offend basic principles of our own common law as well."

Mr Grieve added that anyone suspected of committing offences fighting for groups such as ISIS should be brought to justice through the courts.

Last week, an ISIS fighter who laughed about beheading enemies and spoke of his hatred for the UK in an interview with the BBC was revealed to be from High Wycombe.

Omar Hussain – who called himself Awlaki – said he would ‘only return to the UK to plant a bomb’ in an interview aired by Newsnight last week in the wake of the beheading of American journalist John Foley.

Among the changes announced by Mr Cameron, new legislation would give police powers to confiscate passports of suspected UK terrorists trying to enter and leave the UK.

And the Prime Minister said he plans to hold cross party talks on blocking any British terror suspects from returning to the UK from abroad.

The announcement came a day before chilling new video footage emerged of what appears to be a British jihadi beheading a second American journalist, Steven Sotloff, and warning a Briton could be next.