The director of the Society for the Protection of Unborn Children (SPUC) has written to former Prime Minister Tony Blair to ask whether he will turn back on some of his questionable political positions during his time in office now that he has converted to Catholicism.

Whilst in power, Mr Blair supported abortion up to birth, abortion on girls as young as 11 without the knowledge of the parents, and the promotion of abortion as a human right.

He also supported research on human embryos and gave his backing to the possibility for doctors to dehydrate their patients to death.

John Smeaton, SPUC national director, wrote to the Prime Minister on Friday asking him to admit he was wrong in supporting all such policies.

"While many of our Catholic members will be pleased to hear of anyone's conversion to their church, we have concerns about how Mr Blair behaved both as a backbencher and prime minister," he said.

"This is an opportunity for him to come clean and give witness to the pro-life stance, which we earnestly hope he has now embraced.

"We would hope that, in his various new roles on the world stage, Mr Blair might try to undo some of the harm he has done."

Mr Blair was received from Anglicanism into full communion with the Catholic Church during a service in December led by the head of the Catholic Church in England and Wales, Cardinal Cormac Murphy-O'Connor.

In a visit to the Vatican last year, the Pope took Mr Blair to task not only over his support for easier access to abortion, but also for adoption by gay couples and stem cell research during his 10 years as prime minister.

Mr Smeaton said in his letter, "Your position on pro-life issues and your record as prime minister as a Member of Parliament are a matter of justified concern to people in the pro-life movement, regardless of their faith."