For more than 700 years the parishioners of Trumpington have worshipped in their church while the great crises of the Christian faith have blown about them.

The Crusades claimed the life of one lord of the manor while the building was damaged by reforming zealots during the Reformation.

Nothing in their long history however has frightened the parishioners like the arrival at St Mary and St Michael of a modernising vicar.

In eight years of disturbing radicalism, the Rev Tom Ambrose has moved the harvest festival supper back a day and removed four pews to clear a space for coffee meetings.

When he suggested adding new lavatories for the ageing congregation, the guardians of tradition snapped.

Dr Ambrose must now defend himself against allegations by his parishioners of a “pastoral breakdown” before the first ecclesiastical tribunal of its kind in a generation. Lawyers have said that his legal fees alone could be as high as £150,000 – to be paid by the Diocese of Ely – while the tribunal in York and subsequent appeals could cost as much as £500,000.

Dr Ambrose, a Cambridge graduate, arrived at the parish on the outskirts of Cambridge eight years ago believing that he had a brief gently to modernise the place. But he says that even his simplest plans have been thwarted by a group of angry parishioners who, he believes, are now trying to get rid of him.

“This is not going to do the Church of England any good – to see that Christians behave like this,” he said. “I do not plot and I am a good vicar, but there is a portion of the congregation who have taken against me.

“I wasn’t doing anything terribly radical, I haven’t tried to overturn any traditions, but I made a few changes which I believed would improve the parish.”

He cites the harvest supper as an example. It had been held on a Friday night, with the choir providing entertainment, immediately after choir practice. Dr Ambrose moved it back to an earlier time on Saturday, for the sake of families, older people, and the choir. “In the event we had a much bigger turnout, but instead of welcoming that the Parochial Church Council (PCC) went to the bishop to complain.”

Dissenters also objected when Dr Ambrose removed pews to clear a space where where people could meet for a chat and a coffee after services.

According to John de Bruyne, a member of the congregation who supports the vicar, the final straw for Dr Ambrose’s opponents came when he decided new lavatories were needed.

Mr de Bruyne said: “The lavatories proved an innovation too far. Tom insisted a modern church with an ageing congregation needed lavatories and went to the heritage experts for advice. Parish meetings became heated over where the loos should go. Never have I witnessed such vitriolic abuse and shouting from the old guard.”

Mr de Bruyne, an entrepreneur, said he has now been “frozen out” of the parish, which has a congregation of over 100, because he supported the vicar.

Canon Owen Spencer-Thomas, spokesman for the Bishop of Ely, declined to comment on the likely cost of the tribunal or other details.

Members of the congregation and other local residents have also refused to comment on the dispute, which has split the parish. Philippa Slatter, ward city councillor, refused to comment; Shirley Brown, of the Trumpington Residents’ Association, insisted the matter was sub-judice and would not comment, and Graham Minto, PCC treasurer, has also declined to speak.

Edmund Brookes, secretary of the PCC, said the matter was sub-judice and he would not comment further. No provincial tribunal has sat to hear a case of pastoral breakdown since 1993.

Dr Ambrose added last night that he had greatly enjoyed a recent article in The Times: “Evil-minded parishioners making life hell for clergy”.