The Bishop of Norwich has warned that bat excrement is making churches unhygienic and that he fears a lack of funding to maintain churches could be paving the way for 'a pending crisis'.

The Rt Rev Graham James was speaking in the House of Lords as part of a motion raised to highlight the importance of the English Parish Church.

During the debate, Conservative peer Lord Cormack spoke of 'the menace of the bat' and described how he knew of a church in Lincolnshire where bat droppings were corroding some of the most remarkable 15th century brasses in the country.

He quoted from a letter that from the Church of England Parliamentary Unit that: 'Where there are large colonies it can become intolerable. Churches were built for the worship of God by people. They were not built as nature reserves.

'The impression is that the bats matter much more than the worshipping community — and this is exacerbated by the fact that Natural England have abrogated responsibility... to the Bat Conservation Trust, who are quite legitimately a pressure group.'

In March, Bishop Graham joined Natural England chief executive Dave Webster in a visit St Margaret's Church in Paston, which has a small roost of common pipistrelle bats in the roof.

And, in April, Defra minister Lord de Mauley visited St Andrew's Church in Holme Hale, near Swaffham, to hear how a colony of 260 bats was having a detrimental impact on the historic churches.

During the visit it was heard how the bats were putting people off from going to the Grade I-listed church or using it as a wedding, funeral or christening venue.

In the House of Lords debate, the Bishop said he had worked closely with Natural England, Defra and others on the issue of bats.

But he said: There are positive developments, but it is always odd to me that our parish churches seem to be treated much more as barns than as houses.

'They are places where people gather to worship and to eat—not just the sacrament of holy communion but more socially as well, although I doubt any other eating place would be allowed to be so unhygienic.'

The Bishop also spoke about how, apart from Heritage Lottery Fund awards, congregations generally have to foot the bill for repairing churches, raising £115m a year.

And he said: 'I am conscious that the rising generation of worshipping Anglicans is much less content to take on responsibility for the maintenance of these historic buildings than their parents and grandparents were; they believe that much of what is listed and monitored by the state should be supported by state funds.

'If the economic recovery is as bright as we are told, we ought to look again at the prospects for this huge inheritance of glorious medieval buildings.

'I echo others who say that there are ways in which we might be able to target some of the most testing and hidden parts of our buildings, such as roof repairs, where a grant scheme would be really useful.

'I would be very grateful for the minister's comments on future funding in what I believe to be a pending crisis. Even though our church buildings are in such fine condition now, I am not sure what the future holds for 20 or more years' time.'

• Do you think more needs to be done to protect Norfolk's churches? Write, giving full contact details, to Prospect House, Rouen Road, Norwich NR1 1RE.