Sussex Police today unveiled its latest weapon against crime on the day after four people were convicted of street thuggery.

They will be the first force in the country to pioneer a new pepper spray which has been introduced after it was revealed assaults on officers in one division had soared by 67 per cent last year.

The spray is an alternative to CS gas, which can cause unpleasant after-effects and does not work on everyone.

The force was one of only two nationwide to ban CS gas on the grounds that frequent exposure to it could damage officers' health.

Last year a report also revealed the gas had no effect in 20 per cent of cases.

Now the force will be using a spray called Captor, which is a synthetic version of natural pepper.

The spray is currently in use across the continent in Germany, Switzerland, Belgium and Holland but Sussex will be the first force to use it in England.

Up to 400 police officers in Forest Division, which covers an area from Crawley to Billingshurst and down as far as Steyning, will use the spray from April 2, onwards.

Forest Division has seen assaults on officers rocket in the last year. In 2000 65 officers were attacked compared to 39 in 1999. The division is now hoping to see the assaults drop by at least 40 per cent in line with other forces which use CS spray.

Phil Woolf, press spokesman for Forest Division, said: "The increase in assaults here is partly because we are out there tackling anti-social behaviour every weekend and if you are out there dealing with that kind of behaviour, there's a chance these assaults will happen."

He said because Forest Division encompassed both rural and urban areas, it was the perfect place to test out the spray.

The Captor spray is in a canister the size of a marker pen, kept on a holder on the officer's belt. Compressed air propels it into the attacker's eyes, which will cause a temporary burning sensation.

Unlike CS gas, the effects should completely disappear within half an hour.

Mr Woolf said: "This is directional, like a liquid jet. It should go right where it's aimed, not hang in a cloud like CS gas. It is the next generation of incapacitant.

"It is much less serious than hitting someone with a metal baton."

The spray's active agent is Nonivamide, which is dissolved in a mixture of ethanol and water. Traffic officers, custody staff and dog handlers will all be trained to use the spray.

Superintendent Jim Dale, Forest Divisional Commander, said: "This is a safe, tried and tested product and we believe it will make a significant contribution to officer safety.

"The public has absolutely nothing to fear, but if you are one of the small minority who set out to harm officers, there is the possibility you will be sprayed with Captor."

Sussex Chief Constable Paul Whitehouse said: "Captor is going to make police work safer in Sussex."