MPs pressured the government on Tuesday over support for persecuted Christians around the world.

Tory MPs Chris Green and Fiona Bruce were joined by the DUP's Jim Shannon and others to grill Foreign Office minister Tobias Ellwood on what protections are available for the millions of Christians attacked for their faith.

The debate in Parliament highlighted a campaign to raise awareness of persecuted Christians. The Red Wednesday campaign will take place on November 23 and is run by Aid to the Church in Need. It will ask Christians to wear red or adopt red filters across their social media to highlight the issue. Westminster Cathedral and Westminster Abbey are among a number of prominent sites to say they will light their buildings in red for the cause.

"There were thought to be 1.5 million Christians in Iraq before the invasion in 2003, however that number is now reported to have fallen to 230,000," Green, the Conservative MP for Bolton West, told MPs.

"Whilst many people have been persecuted and have fled from the region, this figure shows the targeted nature of the persecution."

He added that "sometimes the religious context is overlooked or obscured by more dramatic events" but said Christianity was at danger of being eradicated in the Middle East.

In April MPs unanimously voted to declare ISIS crimes a genocide and asked the government to refer the case to the United Nations Security Council. The government has yet to act and Fiona Bruce pressed Ellwood on the lack of progress.

But Ellwood insisted the government was doing all it could to gather evidence of crimes for future legal action. He said that while he agreed a genocide was taking place, it was a matter for judicial courts. "We couldn't get a UNSC resolution put through until the evidence has been gathered," he said. "There is a mechanism we have to go through and that includes the collection of evidence."

He added: "We have to effect change at a pace that will actually work and not have the opposite effect."

Chris Green told Christian Today afterwards the government's response showed how difficult dealing with persecution is.

"If we expect them to behave as we are today when they, as societies, are still evolving - I think that shows a certain arrogance. We have to except they and their cultures will evolve over time."

He added it was crucial the legal process was carried out before declaring genocide.

"We can't be seen to be pushing or usurping the law because we want these societies to recognise law in the same way we do."