Scotland's largest police force may have to cut 25% of its civilian staff in a bid to balance its books, a public sector union has claimed.
Unison said it had an e-mail from Strathclyde Police Chief Constable Stephen House to staff warning of "deep cuts" to the 2,700 civilian posts.
Strathclyde Police refused to comment on the e-mail ahead of a police board meeting next week.
Unison said it could not rule out industrial action to protect jobs.
In the leaked e-mail, Chief Constable House informs senior staff at the force that they are now "entering a critical period in our work to reduce costs and reshape our organisation".
He states: "The next few weeks will see us going to our Police Authority to seek their permission for some new or amended policies that will either directly - or indirectly - affect every person who works for Strathclyde Police.
"They are the policies that will allow us to take forward discussions on changing terms and conditions for officers and staff, offer voluntary redundancy packages and, ultimately take us to a future where Strathclyde Police has fewer people working for it than it has today."
In the e-mail, Chief Constable House said he would tell the Police Authority that the force had no alternative to introducing a recent freeze on police officer and civilian staff recruitment.
He also states that the authority will be told that "we will have to significantly reduce the number of people who work for Strathclyde Police over the next year or two".
The cuts to be implemented, said Chief Constable House, are not likely "to be at the low end of our projections".
He said that if permission was granted, Strathclyde Police would seek to offer an "enhanced package" of voluntary redundancy to staff from next month. This offer, he said, was likely to be a one-off.
Unison branch officer Gerry Crawley said hundreds of civilian post could be lost due to cutbacks.
"The initial view that we have is that there is going to be 400 jobs going in the course of next year followed on by a further 200, and that's because there's going to be a 10% cut in year one and then 5% cuts in the following three years."
Mr Crawley said Unison would consider industrial action as a means of opposing the job losses.
"Industrial action is an option for our members but it's not a course of action we would want to take lightly," he said.
"We would much rather talk to the chief constable and his representatives, and also the Scottish government, because clearly the funding crisis that is happening in Strathclyde isn't just affecting Strathclyde Police, it is affecting police forces across the whole of Scotland."
Councillor Stephen Curran, convenor of Strathclyde Joint Police Authority, said the figure being quoted by Unison was "pure specualtion".
He said: "What we are looking at is a very severe level of cuts next year - perhaps around 10% of the police budget - and we will be looking at a wide range of packages that will hopefully mean that we can protect the level of service for police, and the support staff that they actually provide the service for the police."
Councillor Curran said support staff were "very vulnerable because they can be made redundant far more easily than police officers".
He added: "We have to make sure we have a balanced workforce, and that is really at risk if we don't make serious decisions now with regard to voluntary redundancy and early retirement because we could end up with the wrong people doing the wrong jobs, possibly even police officers sitting behind desks doing jobs they are not meant to be doing."