The 105th Archbishop of Canterbury is expected to use his first day in his new role to declare his opposition to equal marriage, prior to the House of Commons vote on the subject tomorrow.

Justin Welby, 57, will be confirmed as leader of the Church of England in a ceremony at St Paul’s Cathedral later today. He had previously served as the Bishop of Durham for 10 years.

When facing interviews in his role as Archbishop for the first time, he is expected to be questioned about the preliminary vote on same-sex marriage legislation, which takes place tomorrow.

A source close to the Bishop told the Telegraph that he had prepared a response in anticipation of the topic coming up, and said: “If asked he will say that marriage is between a man and a woman, and always has been.”

Bishop Welby has previously said that the church has “no truck with any form of homophobia” and “I need to listen very attentively to the LGBT communities and examine my own thinking carefully and prayerfully.”

He is replacing Archbishop Rowan Williams, who had held the position for ten years. Lord Williams expressed a comparatively liberal approach to homosexuality before his appointment as Archbishop of Canterbury but has overseen Anglican opposition to same-sex marriage.

Archbishop Williams backed the Church of England’s response to the government’s equal marriage consultation, which said legalising same-sex marriage would “dilute” the institution.

The news comes as the Conservative Party sees a split among its MPs over the issue.

23 Tory chairmen wrote to David Cameron yesterday cautioning him about the “growing discord” within the party caused by the equal marriage vote.

A pessimistic estimate by Tory MP David Burrowes claimed that two thirds of Conservatives will vote against the Marriage (Same Sex Couples) Bill, or abstain.