A RUSSIAN Orthodox service of Great Vespers will be celebrated at the Roman Catholic cathedral in Westminster for the first time in its history on Saturday, in what has been described as a “significant step forward” in relations between the Catholic and Orthodox churches.

Bishop Basil of Sergievo, the acting diocesan bishop of the Russian Orthodox Church in Britain, will lead the 45- minute service with the choir from the Cathedral of the Dormition and All Saints, Knightsbridge, at 3pm.

The vespers, which senior representatives from the Greek Orthodox and other churches will also attend, marks the beginning of the 96th Week of Prayer for Christian Unity. It is understood that the Archbishop of Westminster, Cardinal Cormac Murphy-O’Connor, who is recovering from a hip replacement operation and whose official duties do not begin again until next Monday, might look in briefly if he is feeling well enough.

Archbishop Gregorios of Thyateira, head of the Greek Orthodox Archdiocese in Britain, who will preach at Mass at the cathedral on Sunday, celebrated a Greek Orthodox vespers at Westminster seven years ago to the day on Saturday, but although the Russian church took part in a unity service in 1973, there has never been a full Russian service there before.

Pope John Paul II has considered it one of the aims of his pontificate to bring Eastern and Western churches closer together again. He has often described the East and West of Europe as being the “two lungs of a single body”.

However, relations remain tense. The Russian Patriarch of Moscow, Aleksei II, has accused the Catholic Church of proselytising through the re-establishment of Catholic dioceses in his territory. He has restricted the movement of Catholic priests in his diocese and has held out against a papal visit.

In Britain, though, relations between the two churches have been and remain good. The late Cardinal Basil Hume was active in fostering friendships with leaders of the Orthodox communities in this country.

Bishop Basil, who is run-ning the Russian Orthodox Church in Britain after the recent death of Metropolitan Antony of Sourozh, says: “For me, the vespers fits into the normal pattern of the Russian Church’s presence here in this country. We have to make a fairly clear distinction between relations between the Orthodox and Roman Catholics in this country and the situation that applies in Russia and parts of Eastern Europe. I would consider the situation to be completely normal here. In other parts of the world relations are strained, but that is a result of local situations.”

In his sermon he will take as his theme the Feast of Theophany on Monday, the Orthodox celebration of the baptism of Christ, emphasising the common baptism of Christians who belong to different churches.

He says: “What is interesting is the relationship between Christ’s baptism and ours and the way in which it is Christ who sanctifies the waters. It is his presence that makes the waters of the Jordan sacramental. We enter into that by relationship with the baptismal waters. So there is a connection between the baptism of Christ and our baptism. And of course baptism is one of the things that joins us all together today.”

The Right Rev James O’Brien, the senior auxiliary bishop in Westminster and chairman of the diocese’s ecumenical commission, said: “I am quite delighted that the Russian Orthodox community in London has decided to celebrate a vespers in Westminster Cathedral.

“The relationship between the Russian Orthodox and Catholic churches has had its ups and downs, certainly, in recent years. It has been one of the aims of the pontificate of Pope John Paul II to bring the Church of the East and the Western Church together. It is a marvellous thing to see this gradual healing taking place. This service is a significant step foward.”

The split between East and West was formalised in 1054 when the Pope and the Patriarch of Constantinople excommunicated each other in a clash over the primacy of Rome.