Job losses among Avon and Somerset Police civilian staff will "inevitably" affect policing, a union has claimed.
Nearly 200 members of staff are to lose their jobs as the authority tries to cut £40m in the next four years.
Unison said the cuts would affect front line services as many of the workers were 999 operators and people who help gather evidence.
After the announcement, Chief Constable Colin Port said it was a "dark day" for his force.
Janet Govey from Unison, which represents civilian police staff and other public sector workers, agreed with that statement.
She added: "We don't know the full details but inevitably the loss of this number of police staff posts is going to have an impact on the policing of the communities we live in.
"Police staff are not all doing background office stuff. They are investigators in major crimes unit - a lot of the people seen on TV investigating the Christmas murder (Jo Yeates) would have been police staff."
The cuts will also see a call centre in Taunton relocate to the force's headquarters in Portishead. It is not clear how many jobs will be affected but management has started a consultation period.
Ms Govey said a lot of the staff in call centres were part-time workers, many of them women, whose personal circumstances may mean they could not easily relocate.
Avon and Somerset Constabulary employs 2,500 civilians and 3,200 officers.