The Catholic Archbishop of Southwark Peter Smith has been criticised for claiming that most Catholics who support equal marriage would be prepared to leave the Church over the issue.

The Most Reverend Peter Smith made the comments in front of a committee of MPs that are studying the government’s Marriage (Same Sex Couples) Bill for England and Wales.

However, Labour MP Siobhain McDonagh, who is Catholic, was not impressed with Archbishop Smith’s opinion, she replied: “Your Grace, I am sorry, but I cannot let the comment go that Catholics who support gay marriage or gay people, or oppose the Church’s teaching on abortion or divorce, would probably leave the Church.

“I think all those things, and I am never going to leave the Church. I am a practising Catholic, and I have to say to you that there are vast numbers of people, certainly in parishes all round south London, who share my particular view.”

Ms McDonagh, who represents the south London constituency of Mitcham and Morden, went on to say: “I am concerned that you have presented today a view of the Church to many people who will not be cognisant of the Catholic Church that is different from how it operates.

“Catholic schools have always been able to explain their view on abortion, divorce and all sorts of things at the same time as carrying out their responsibilities to young people in teaching sex education and in moral teachings.

“There is no dilemma about that. We all understand it, but it has been done with kindness and courtesy. What disappoints me is the way that we are falling into legalese to show the Church in a very unkind and uncaring way.”

When asked by Labour’s shadow equalities minister Kate Green if he accepted the reality of gender reassignment, Archbishop Smith replied: “I do not accept that we can change someone’s gender. There is a real difficulty when it comes to what is called gender dysphoria: somebody who is very inclined to think someone is opposite to what they are.”