Senior police defended its controversial community support officer scheme after one of its officers said it was a waste of money.

PC Nick Dimmer yesterday described the scheme as a "false economy" in front of hundreds of officers at a national conference held by the Police Federation, which represents rank-and-file police.

His comments - backed by the Sussex branch of the federation - come at a time when Sussex Police is planning to more than treble the size of its community support team at a cost of millions of pounds to taxpayers.

PC Dimmer said: "We have two CSOs walking down the road at a time, each costing £18,000. That's £36,000.

"A police officer on his own is £21,000. It's a false economy."

Constables at the conference in Bournemouth jeered and heckled police minister Hazel Blears as she insisted: "As far as we are concerned CSOs are here to stay."

CSOs were introduced in September 2002 after reforms by Home secretary David Blunkett, and were dubbed "plastic policemen" and "Blunkett's bouncers" by critics.

With 74 officers, Sussex has one of the largest CSO teams outside London. The force is recruiting a further 150 this year and is asking the Home Office to fund a further recruitment drive. CSOs start on £17,412 to £19,055 a year. They have the same common law powers of arrest as members of the public and cannot detain suspects.

They get a radio, a mobile phone and body armour but they are not provided with handcuffs or batons.

Their job is to reduce fear of crime by contributing to a better uniformed police presence on the streets.

They deal with minor offences and carry out house-to-house inquiries, act as crime scene guards and provide crime prevention advice.

Training consists of two weeks behind desks learning about health and safety, unarmed defence training, first aid, diversity and legislation.

After supervised patrols they are sent out on their own, monitored by sergeants.

The Sussex scheme, funded by the Home Office and a variety of statutory bodies, is guaranteed until at least 2006.

The Sussex Police Federation yesterday supported PC Dimmer's comments and said there was concern among officers the "extended family" of civilian officers might expand at the expense of ordinary beat bobbies.

Federation chairman Graham Alexander said: "Our view is the extended police family should supplement the work of of police officers and not supplant them.

"It is early days and we do need to be sure the work of PCSOs is properly evaluated.

"We are rushing at this and we are not giving it perhaps the critical thought that needs to be given.

"There is no problem whatsoever with increasing police civilian staff but if it is at the expense of police officers then that is a worrying trend for the future."

Sussex Police assistant chief constable Nigel Yeo said: "It is a matter for local commanders as to how police community support officers and constables are deployed.

"There is nothing stopping police community support officers being deployed singularly or constables in pairs.

"It is a matter of circumstances, and what is sought to be achieved, taking account of the public's needs in the way of reassurance and performance.

"The argument for police community support officers does not stand or fall on their relative salary costs. Their role is not a cheaper alternative to warranted police officers, they perform an additional function."