Plans to outsource the sterilisation services based at Chorley Hospital have been dubbed "privatisation by the back door" by unions.

The Hospital Sterilisation and Decontamination Unit (HSDU) cleans and sterilises surgical equipment used in operating theatres. It employs around 25 people and provides a 24-hour in-house service to the hospital.

But health chiefs are planning to join with three other hospital trusts to employ a private operator to provide the service from an off-site location. Rob Yates, director of professional support services for the trust, blamed the move on legislation issued by the Department of Health to comply with revised European standards being applied to sterile services.

Janet Howarth, Unison representative at Chorley Hospital, said: "We disagree with the current policy regarding sterilisation services as we see it as privatisation by the back door."

One worker at HSDU in Chorley, who did not wish to be named, said: "It is a state-of-the-art department here, close to the doctors and surgeons who need the equipment. I don't feel there is any need to move us and take us out of the health service.

"Our unit is equipped to deal with equipment contaminated with MRSA and HIV and has had large scale investment in the last couple of years. There just seems no reason for it."

The Lancashire trust has linked with Knowsley and St Helens, Ormskirk and Southport, and Blackpool hospital trusts.

It is believed there are two firms bidding for the contract. One would build a unit at Buckshaw, the other would base the facility at Red Scar in Preston, or a location in Southport.

Mr Yates said the plan was being done in consultation with staff representatives at national and local level, and if it goes ahead, staff will have statutory rights to transfer to the new service or be given alternative job ats the trust.