It is one of the nation’s best loved hymns and a favourite of Gordon Brown's. But William Blake’s Jerusalem will no longer ring from the spires of Southwark Cathedral after it was banned by the church’s dean on the grounds that it was unchristian and too nationalistic.

Regarded by many as a paean to Englishness, it has over the centuries become an unofficial national anthem, sung at the last night of the Proms and by England rugby and cricket fans. It is such a favourite of the Women’s Institute that a recent BBC drama based on the group was titled “Jam and Jerusalem.”

But the Very Reverend Colin Slee believes it is not “to the glory of God” and as such should not be sung by choirs or congregations at the South Bank cathedral, on of Britain’s foremost churches.

The ban came to light after the dean advised guests at a recent memorial service that it could not be sung due to its lack of religious content.

A spokesman for the Cathedral later revealed that the dean had not allowed it to be included in services for some time.

"The Dean, on common with all other cathedral deans, has the authority to decide what material is used in liturgy in the cathedral," he said.

"The hymn Jerusalem is often used on national occasions, although rarely in Southwark, even on such occasions.

"The Dean of Southwark does not believe that it is to the glory of God and it is not therefore used in private memorial services."

The words of the hymn are a poem by William Blake, which starts: “And did those feet in ancient time/ Walk upon England’s mountains green?”

The verses, written in 1804 as a preface to Blake’s epic poem Milton, are said to be based on a legend that Jesus Christ came to England as a young boy and visited the Somerset town of Glastonbury. It is linked to a section in the Book of Revelation describing a Second Coming in which Jesus establishes a new Jerusalem.

The idea of Jerusalem is often used as a metaphor for Heaven by the Christian Church, particularly the Church of England. Though interpretations of the poem differ, it is often seen as suggesting that Jesus briefly created heaven in England and that we should strive to re-establish this once more. The reference to “dark Satanic mills” is usually thought to allude to the early industrial revolution and the damage it wreaked on nature and the poorest sections of society.

The words were set to music by Sir Hubert Parry in 1916, as an anthem for the suffragettes’ movement.

It is not the first time the hymn has been deemed unchristian by the clergy.

In 2001 it was banned from a Manchester wedding ceremony because the vicar thought it overly nationalistic and inappropriate to the occasion.

Meanwhile the parish church of Parliament, St Margaret's in Westminster, has excluded it from services in the past on the grounds that the "dark satanic mills" discriminated against city-dwellers.

For much of the 1990s it was banned by St Paul's Cathedral but the church has now relented.

Three years ago, Mr Brown told BBC One's Songs of Praise that it was his favourite hymn, while in the Euro 2000 tournament it was made the official anthem of the England football team.

Brian Hoare, chairman of the Pratt Green Trust, a charity which promotes religious music, said: “It’s not a hymn I would personally choose. It’s a good piece of music and it’s a very patriotic hymn, if you can call it a hymn.

“It’s not really a devotional hymn. As a tool for Christian worship, I don’t think it meets the requirements."

But a Church of England spokesman defended the hymn, which he said was "widely-loved."

"It is firmly fixed in generations of hymn books and has its rightful place in Church of England worship.

"It is always important when arranging funerals or memorial services to discuss with the priest which hymns are appropriate."