A fifth of Brighton and Hove's churches have been earmarked for closure including the city's landmark parish church.
Parishoners and clergy have spoken of their shock after the move by the Church of England, which would also lead to a dramatic cut in the number of vicars.
Similar cost-cutting drives are planned for the rest of Sussex and reviews are already underway in Hastings, Eastbourne and Chichester.
Only 1.7 per cent of the population of the city attends services at Anglican churches and the C of E says there is little point paying to keep them open.
St Peter's Church in York Place, the parish church of Brighton, and St Mary the Virgin in Bristol Road, Kemp Town, are among victims of falling congregations and church leaders say it is too expensive to run them.
The others are: Christ the King in Braybon Avenue, Patcham; St Albans Church in Natal Road; The Church of The Holy Nativity in Norwich Drive, Bevendean; Stanmer Church in Stanmer; Holy Trinity Church in Blatchington Road, Hove; St Julian's Church in Kingston Buci, Shoreham; St Leonard's Church in Aldrington and St Barnabas in Sackville Road, Hove.
Closure of the churches has been recommended by the Deaneries Pastoral Strategy Review Group in a report called Towards Revitalisation of the Church of England Deaneries of Brighton and Hove - the Next Steps.
Six churches in Brighton and four in Hove would close, with some being sold to private developers to be made into houses or businesses.
Another 11 churches have been put under review and could also face the axe if congregations become too small.
Vicars who retire are not being replaced and the number of clergy is being cut with team ministries being brought in to replace the old system where each parish church had its own vicar. More pressure is being put on lay helpers to keep services running.
The Church of England hopes St Peter's can be kept open as a community centre but conservationists are worried that would not generate enough income to maintain the building and could end up abandoned and decaying like Brighton's West Pier.
Archdeacon of Chichester, Father Douglas McKittrick, was vicar at St Peter's Church for five years between 1997 and 2002. He said: "Some of these buildings we would like to develop to be a greater and wider Christian service, rather than just a place of worship.
"Our buildings can be used in a much wider way than they are at present.
"The church mission is much bigger than those buildings."
Rev Trevor MacDonald, lay vicar of St Barnabas in Sackville Road, Hove, was annoyed his church had been earmarked for closure only five years after a £200,000 restoration project which he had put a lot of his own money into.
Selma Montford, secretary of The Brighton Society conservation group, said: "By far the most important building is St Peter's Church. It is very important to the landscape of the city.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article