Heroin worth thousands of pounds was discovered in the bend of a drain by police raiding a squalid drugs den.

The "significant" find came as the crowning moment of a two-day police operation in a bid to sweep the city of drug dealers and burglars.

During Operation Entry, six officers with sniffer dogs broke down the front door of the flat in Brighton.

A man was discovered crouching over a toilet having just flushed it.

Southern Water were called in to open up the drain and a bag of heroin with a street value of at least £5,000 was found in the bend.

It is believed the officers' swift actions meant the drugs were not flushed away completely.

Police seized an array of syringes, drugs and weapons.

The Army had to be called in to attend to what appeared to be a small green grenade launcher.

They also took away what may have been an incendiary device discovered in the kitchen.

Sergeant Brian Bell, in charge of the raid, said: "It may have the potential to have an explosive effect but at this stage we cannot be sure. The bomb disposal unit has taken it away for analysis."

Twenty-five samurai swords covered the walls of the flat.

Police found six handguns comprising air pistols, starter pistols and replicas in the bedroom. They also discovered several .22 calibre bullets.

Six syringes full of what was thought to be heroin were found hidden under a mattress and in bedside cabinets.

Sniffer dogs traced various bags of what was believed to be skunk cannabis scattered around the flat.

One man was arrested during the raid.

During the two-day sweep more than 40 people were arrested on suspicion of drug dealing, burglary and car crime.

Stolen property, crack cocaine, cannabis, heroin and coshes and knives were seized. A total of 41 people were arrested.

Those arrested, 29 men and 12 women, were all in their 20s and 30s. They were detained at addresses in the Whitehawk, Moulsecoomb, Kemp Town, Hollingbury and Seven Dials areas of Brighton and one in Hove.

Mr Bell said: "It was a very significant find."

Police revealed the raids had blocked moves to set up organised crime in the city.

Superintendent Peter Coll, in charge of this week's police raids, said: "The seizure of weaponry is good news for the people who live and work in the city and we will continue to focus on drugs and violent crime this summer, in line with force and Home Office priorities."

Acting Detective Chief Inspector Vic Marshall said: "It has been incredibly successful and it will have a real impact on police performance nd, hopefully, the public.

"There should be fewer burglaries, drug dealing and car crimes, especially if we can take our top suspects out of circulation for a long time."

More warrants were being executed in London to arrest suspects wanted for Brighton crimes.