Police have warned a series of dawn drug raids in which a bag of heroin was seized are the first of many.

The drugs, with a street value of thousands of pounds, were found buried in the back garden at one of nine addresses targeted by police in Horsham and Crawley.

Eight people were arrested in the second major operation in less than two weeks.

The officer leading the operation, Chief Superintendent John Dransfield, vowed this was just the start.

He said: "It has been very successful. We have hit five of our main targets. To our minds they are prominent drug dealers in the area and we are still working on more.

"There are other addresses we have yet to go to. We are aware of other drug dealers in the area and this is giving them notice."

The raids were launched as part of a force-wide clampdown on the supply of heroin and crack cocaine.

Two weeks ago, raids were carried out at 16 addresses in Haywards Heath and Burgess Hill. Eight people have since been charged with being concerned with the supply of Class A drugs and have all appeared in court.

Chief Supt Dransfield said: "At one stage we were looking at launching the raids at the same time as Mid Sussex but for operational reasons and the timing it was not possible.

"This is just the start of it and we have been looking at this for some time. There will be more arrests throughout the coming months.

"We did not anticipate finding significant quantities of drugs. We had done all our background intelligence on who is supplying in the area rather than when the supplies were coming in.

"This type of operation takes six months to prepare.

"Unfortunately, for the foreseeable future we will never be fully satisfied that we have stamped on the menace because it is too easy to start up."

More than 120 officers yesterday executed eight search warrants in Furnace Green, Three Bridges, Southgate, Broadfield, Pound Hill and Northgate as well as Horsham.

Drug abuse causes misery to thousands - the users, their families and the victims of crime, such as car crime, robbery and burglary committed by addicts desperate to raise funds to pay for the next fix.

Crack cocaine is cut with baking powder, often formed into one-gramme "rocks" which sell for about £20.

Research shows that heroin users smoke, inhale or sniff it as a "treat" when they have sufficient funds available, often spending £200 a week to feed their habit.