Community groups leasing council-owned buildings fear they would be unable to operate under new proposals to increase rent.

Norfolk County Council is seeking to make voluntary organisations using its properties to pay rent at full market value.

Until now, many groups, including sports clubs and charities, have been able to use council-owned assets at a peppercorn rate.

The local authority said the change would lead to greater transparency and ensure all potential occupiers are treated in a consistent manner.

Members of the policy and resources committee were told yesterday that any additional rental costs could be offset with grant funding. However, it was noted that this would only apply to service providers that support council strategies.

Steve Morphew, Labour councillor, said an unexpected rent hike could leave some groups feeling 'extremely vulnerable'.

'When it comes to organisations asking for a grant, what are the restrictions? Does there need to be an annual review,' he said.

'By going down this line, does it mean we will have the sword of Damocles hanging over a couple of organisations every single year?'

While private companies using council buildings have to pay full market rent, many voluntary groups are given a reduced rate.

The Silver Road Community Centre is one of almost 1,000 tenancies using council buildings across the county. Based in the former Silver Rooms in Norwich, it was given access to the building on a £1 peppercorn rent for 25 years. Julie Brociek-Coulton, manager, said: 'If the council was to make us pay a full market rent, we would have to close as we just about make ends meet. We do not charge a big rent [to users] as we are a community centre, and if we did, we would start losing groups.'

Committee members raised concern about the wording of the recommendation, and asked for more information before agreeing to defer a decision.

George Nobbs, Labour councillor, said the list of organisations applying for grants under the new system would be 'enormous'.

He added: 'There is nothing whatsoever here to say that we will compensate for the catastrophe some of them will find themselves in.'

A council spokesman said: 'The intention of today's report was to develop a consistent and transparent policy in relation to new tenancies.

'Most of the existing tenancies will be unaffected by the proposed policy due to the terms of the lease. As part of any rent review process the tenants, or their representative, are kept informed.'