The Calderdale bureau will lose £20,000 of its £400,000 council grant this year with a further reduction a year later.

But, in a confidential report seen by the Courier, bosses claim cuts mean the service will lose £341,000 in real terms over the next five years.

One option is to close all offices except Halifax and run drop-in surgeries in other areas. The other options suggest keeping Halifax and one other office open in either Todmorden or Hebden Bridge.

The bureau's chief executive Matt Mills states: "The size of these reductions means there is limited scope for absorbing them through small savings on minor budget lines

"We consequently need to look at making savings through reducing actual operations and operations costs, i.e. the closing of centres and reducing staff numbers."

A former bureau service user said such cuts would have a devastating impact on the most vulnerable residents of Calderdale.

"People will have to travel out of their home town," she said.

"If they have health, mobility or money problems, that is going to be very difficult, especially if Todmorden closes – imagine going from Cornholme to Halifax when your benefits have been stopped."

The advice centres provide free, independent and impartial advice to over 13,000 people every year. Trained advisers, most of whom are volunteers, currently help people in Brighouse, Elland, Hebden Bridge, Todmorden and across Halifax, where there is a permanent office on Harrison Road and various drop-in centres.

"There are areas of social deprivation, and for them to lose the service would be devastating," said the women, who did not wish to be named.

"People need help with legal access, spiralling debt problems and benefits."

Workers fear that the organisation is being incrementally dismantled by council budget cuts. They fear volunteers will be lost as sites close and there is less space for consultations.

The report shows the current £400,000 budget will be cut to £380,000 this year.

That will drop to £355,000 next year and then rise slightly over the following three years to £381,000 in 2011/12. The service had expected an income of £462,000 by that time, if the current budget increased in line with inflation.

Mr Mills confirmed the report would be discussed next week by the Citizens' Advice Bureau trustees.

A statement from Calderdale Council made light of the bureau cuts.

Amanda Byrne, portfolio holder for community services, said: "Calderdale Citizens' Advice Bureau has used the council's funding to provide a quality advice service across Calderdale for many years now, and it is still the organisation that receives most of the money available to us for these legal advice services.

"This reflects the council's confidence in the excellent service provided by the bureau.