The prime minister has appointed Fiona Bruce MP as his special envoy to promote freedom of religion and belief internationally.

Mrs Bruce, who is a Christian, has pledged to champion the causes of persecuted groups like the Uighur Muslims in China and the Yazidis in Iraq.

Announcing the appointment, Boris Johnson said: "The UK is absolutely committed to protecting the inalienable right to freedom of religion and belief, at home and around the world.

"As we approach Christmas, the season of peace, people of all faiths and none are still being persecuted for their beliefs.

The prime minister added: "I am delighted to appoint Fiona as my special envoy on this issue, and I know she will be a passionate advocate for tolerance and freedom."

Mrs Bruce has highlighted the plight of Leah Sharibu from Nigeria and Maira Shahbaz from Pakistan, two young girls who were "brutally abducted" from their homes, as cases she will champion.

The Congleton constituency MP said: "I am honoured to be given this opportunity to serve as the prime minister's Special Envoy for Freedom of Religion or Belief (FoRB). There is much to do, and my post will be placed at the service of some of the most vulnerable people across the world.

"Having travelled to countries such as Myanmar, Nigeria and Nepal and heard first-hand accounts of atrocities and persecution being meted out there, I know how much those who are suffering from this appreciate advocacy on their behalf, even from afar. I was reminded of this movingly only recently following a meeting with Leah Sharibu's mother Rebecca,

expressing appreciation to UK Parliamentarians that her daughter and others 'held in captivity are not forgotten about or disregarded.'"

The foreign secretary, Dominic Raab, said that through this role the UK would be "acting as a force for good" in the world.

Humanists UK has expressed alarm at the appointment, citing Mrs Bruce's stance on issues such as abortion and LGBT issues.

Andrew Copson, the chief executive of Humanists UK, said: "We are not alarmed by Fiona Bruce's appointment because we hold any personal animus against her, but because her record both shows her to be an opponent of freedom of belief for the non-religious, and as someone who does not treat freedom of religion or belief as one of a family of human rights that are universal, indivisible, and interrelated.

"Her actions and convictions are perfectly legitimate in a free country but they are incompatible with the UK's stated commitments on FoRB.

"We have written to the Prime Minister and Foreign Secretary to convey our concerns and the harm that this appointment will do to FoRB both at home and abroad."