The motion calls on the Government to table a resolution at the UN Security Council

MPs have voted unanimously to declare that ISIS is committing genocide against Christians, Yazidis and other groups including some Shia Muslims. The vote will increase the pressure on the Government to take action.

The House of Commons voted by 278 votes to 0, with backing from all major parties, despite official Government opposition. The Foreign Office directed ministers and Government aides to abstain from the vote.

The Government has said that genocide is a legal term not to be used without legal authority. The motion calls on the government to refer the matter to the UN Security Council with a view to involving the International Criminal Court, to bring ISIS leaders to justice.

The US Secretary of State, John Kerry, declared last month that ISIS was committing genocide. He had previously resisted such calls, but came under pressure after a unanimous vote in the House of Representatives.

In her speech, Fiona Bruce, the MP who proposed the motion, said: “never before during a genocide has the international community had such a full record of what was happening”.

She described instances of ISIS killing and torturing Christians and Yazidis. She mentioned eyewitness testimony including that of a young Yazidi woman. “At the age of 15, she saw her father and brother killed in front of her, and told of how every girl in her community over the age of eight, including herself, was imprisoned and raped. She spoke of witnessing her friends being raped, and of seeing a girl aged nine being raped by so many men that she died. Many young girls had their fragile bodies rendered incapable of pregnancy, and others, far too young to be so, were made pregnant.”

The Foreign Office minister Tobias Ellwood, speaking for the Government, condemned ISIS’s actions but did not say the Government would take action.

“This ultimately is a matter for courts to decide. It is not for governments to be the prosecutor, the judge or indeed jury,” he said.

The Conservative MP Edward Leigh said in response: “There’s no point in the minister using his time in the House to condemn Daesh [ISIS], to mention all the appalling acts that they’re doing and then saying at the end of the speech: ‘Well, I’m sorry, but because of all the legal precedent… because we the Government think that it’s for the court to take the legal initiative, that we don’t think it is appropriate for the British Government to take action. Enough is enough. I call on the Government to act.”

Lord Alton, who has tabled a similar amendment in the Lords, which was defeated after Government opposition, said after yesterday’s vote: “The House of Commons has spoken and the Government now needs to stop prevaricating, listen and act.

“The Government also needs to address the absence of any formal mechanism to refer evidence of genocide to the Courts, which simply leads to Government buck-passing and hand ringing. They repeatedly say that determining whether a genocide is underway is a matter for the courts but then refuse to provide a trigger for a referral. Parliament – as Congress and the European Parliament have done – has had to force the Government’s hand.”

Lord Alton said that if ISIS’s actions did not meet the standard of genocide set out in the 1948 Genocide Convention, to which the UK along with 146 other countries is a signatory, then nothing did.

The shadow foreign minister, Diana Johnson, said the Government should recognise the legitimacy of Parliament and table a resolution at the UN Security Council.