City drug addicts are risking their lives with a lethal cocktail of heroin and crack cocaine.

Drug workers in Brighton and Hove say 'speedballing' - blamed for the death of Hollywood icons John Belushi and River Phoenix - is tightening its grip in the area.

The practice involves injecting heroin and cocaine simultaneously to combine the calming effects of the opiate and the energy rush of the stimulant.

Agencies in the city say more and more people are taking their lives into their hands by experimenting with the lethal concoction.

Workers from Brighton based addiction charity Addaction first received reports that the phenomenon had reached the city two years ago.

Now they have 'street' intelligence that it is becoming responsible for more of the high number of drug related deaths in the city.

Users inject crystals of crack cocaine, which are not easily dissolved and can lead to blocked arteries.

Crack is also an anaesthetic, meaning it can numb nerve endings, leading to a risk of users injecting directly into an artery.

Charity spokeswoman Rosie Brocklehurst said no official statistics existed but anecdotal evidence suggested speedballing was on the increase.

She said: "The message we want to get out is speedballing is dangerous. It is not only potentially lethal to use heroin and cocaine together, it is also very dangerous to inject crack cocaine in crystal form.

"We know this phenomenon is growing in Brighton and we know it is very unsafe. That gives us sufficient grounds to be concerned."

More than one person a week died from drugs in Brighton and Hove last year.

Figures published by the European Centre for Addiction Studies in October, showed the city had a drugs-death rate of 28 per 100,000 of the population over the age of 16, the highest in the UK outside London.

Mrs Brocklehurst said: "I do not know of any fatalities directly linked to speedballing but I presume it has played a part in causing deaths because we know it is a growing phenomenon."

The emerging trend is causing problems for drug workers and doctors, who use varying methods to wean addicts off different drugs.

Addaction director Kevin Molly says speedballing is practised by 20 to 30-year-old heroin users and cocaine smokers, who tend to be younger.