Uncertainty looms for human resources staff at Kingston and Sutton councils after the authorities announced plans to merge more back-room services.

The councils will begin sharing human resources (HR) from April as a cash-saving measure - they already share IT and legal services - but both said they did not know how many people were at risk of redundancy.

In May 2015 Merton council gave notice on the then-shared HR service with Sutton, putting £787,000 of savings at risk and prompting the merge with Kingston.

A report to Sutton's strategy and resources committee meeting last month did not set out how many people will lose their jobs or how much the amalgamation will cost, only that "staffing implications relating to the decoupling of services are not yet possible to fully clarify".

Sutton Council leader Ruth Dombey said: "Sutton has been at the forefront of sharing services. We now share 15 services with other councils and that has saved us £8m.

"This will not exclude consideration of other partners when looking at how to best deliver high quality efficient services to Sutton residents.

"We all believe that a problem shared is a problem halved."

Kingston Council leader Kevin Davis admitted he did not know offhand how many people worked in the HR departments and how many would end up losing their jobs.

He said: "Inevitably there will be some job losses but these will probably not have been decided yet.

"What we need to focus on is the fact that Kingston has to save an enormous amount of money over the next few years.

"We knew the Government grant we get was going to decrease but it is far smaller than we ever expected."

Kingston councillor David Glasspool, cabinet member with responsibility for treasury, said: "If we did not enter into this new arrangement it would be likely that our costs and headcount would need to rise.

"We will be working on the design of a new structure to ensure that we have the most efficient and cost-effective service.

"The implementation of the new structure may lead to some staffing changes but at this stage we cannot confirm whether or not there will be any overall reductions."

It is the most recent service to be shared between the two boroughs with a merger of highway services, environmental health and trading standards approved in June 2015 to save £580,000 per year between the two councils.

All redundancy costs will be shared.