PROPOSALS to save £500,000 by outsourcing bin collections, park maintenance and street cleaning in Worcester to a private firm are facing fresh criticism - with the figure based largely on calculated guesswork.

Worcester City Council has admitted its forecasted 'saving' on handing over most of its cleaner and greener department is modelled on comparisons with other local authorities who have done the same thing.

Across the country, more and more councils are handing over the services to outside companies under specific contracts.

The typical yearly saving elsewhere is between seven and 15 per cent, which is why the council has aimed for a target of £500,000 - 10 per cent of its £5 million yearly spend.

It has led to concern from opposition councillors, who say they harbour serious doubts that it can be achieved.

Councillor Paul Denham, from Labour, said: "The examples I've seen from elsewhere shows that privatisation doesn't actually save money, it costs more.

"It is very hard to see how a private company can achieve these sort of savings by providing the exact same service at a lower cost.

"It seems like the figure has just been dreamt up from anywhere without a thought at all - we looked at this last year (when Labour was in control) but nobody has ever given us any confidence in it."

The Conservative leadership says the change, which will not kick in until 2017, gives the council time to see if the projections are realistic.

Councillor Simon Geraghty, the leader, said: "If seven to 15 per cent is the average saving that has been generated from all the other deals, 10 per cent doesn't seem an inprudent figure.

"We're not talking about doing this now but in three (financial) years, and we are confident it can be achieved without affecting service standards.

"There is little risk in allowing this proposal to go forward but a lot of risk in not doing this now - the alternative is to bury our heads in the sand and then find in year three, we've got a problem and need to make cuts."

David Sutton, head of the cleaner and greener department, said: "Ten per cent is a reasonable figure for us to use, but it's at an embryonic stage."

If it goes ahead it would mean 120 jobs, from a total council workforce of 270, being transferred over to a private firm.

Under the proposal the cemetery and burial services, and car parking would remain in-house under a slimmed-down cleaner and greener function controlled in-house.

The Tories also say the council will stay in control and ownership of its assets, like the parks, with only the actual maintenance of them being done by an outside firm.