Businessmen will sit down with bishops and homeless people with politicians including Tony Blair for the main event at Banqueting House.Honest about his own doubts, Father Seed does not ask those he is instructing to accept all the difficult tenets of the Catholic Church, including papal infallibility and praying for the dead – many of which he still struggles with himself. When not seeing would-be converts, he has proved an energetic campaigner: in 1991 he raised pounds 10,000 for a project to help the homeless by compiling a book in which famous people including Lord Wilson and Bono of U2 described their ideas of Heaven. Many of the friars work as ecumenical officers in the US, where the order is strongest and where he gained a doctorate in theology.Father Seed has now been at Westminster Cathedral for more than 10 years. He was also sacked from a clothes shop for telling customers they could dress more cheaply elsewhere.

After a string of other jobs he became a priest, and joined the Franciscan Friars of the Atonement, an order formed in 1898 to work for church unity. It was a church of sinners to me, because at that time alcohol was a sin and I wasn’t allowed to do anything, even go to the cinema.”He had left school withoutqualifications, and was fired from a job in a motorway cafe for breaking plates and putting an electric kettle in the oven (as an institutionalised child he had never made tea before). But it was the smell of incense and drink that caused him to convert, at the age of 17.”One evening I went into a Catholic church which was next to a pub,” he has said. “Half the congregation was saying the rosary, the priest had his back to them, it was totally in Latin: absolutely dull and boring and dreadful, but absolutely packed All I could smell was incense and alcohol I had a kind of conversion experience. He became a member of the Strict and Particular Baptist Church, which taught that both Catholicism and alcohol were ungodly. The other children used to insult me.”His adoptive father and grandfather were also dead within two years, so he was raised by his elderly grandmother, a staunch member of the Salvation Army. He had what would now be called learning difficulties: he could not read or write properly until he was 12, went to a special boarding school, and still describes himself as dyslexic.

He was an adopted child, with a turbulent childhood: “My mother killed herself on a railway track just outside our house when I was seven,” he has said “I had to cross that track every day to get to school. While greeting the conversion of Ann Widdecombe in 1993 as “an authentic movement of the Holy Spirit”, he told the congregation at her first communion that there must be “no hint of triumphalism”.Perhaps that is because Michael Seed was a convert himself, with a background in several other kinds of Christianity. He turns down media requests to talk about his work, because of “the deeply personal nature of discussions between a priest and those who are seeking to develop their spiritual life” and because he is unhappy about drawing attention to himself and appearing to denigrate other Christian traditions he respects. As Cardinal Hume’s ecumenical adviser, he also has to deal with priests from other churches. In the case of Anglican clergy, that increasingly means helping them to convert.But you will not hear Father Seed gloat about this growing tide. The Duchess of Kent learnt from him before she was received into the Church in January 1994. At Parliament he isas likely to be found talking to the cooks, cleaners or other staff as the politicians.