Kenneth Costello was found with 206g of the potentially fatal Class A drug stashed in the hood of his cooker after cops armed with a search warrant turned up at his flat in June.

It followed reports of him dealing drugs from the property.

The 36-year-old was also found to be storing 11kg of a highly sought after black market mixing agent called Bash — a mixture of paracetamol and caffeine — which is used to bulk out heroin and maximise a dealer’s profits.

Last week Sarah Healing, prosecuting, told Dumbarton Sheriff Court that there was no-one inside Costello’s Whiteford Place flat when they arrived but assumed he had only recently left as the TV was on and there was cigarette smoke in the air.

A search was carried out and Costello was soon found in a neighbour’s property and detained.

Officers then found two knotted bags filled with brown powder, which was later analysed and found to be heroin which was 13 per cent pure, in the hood above the cooker in the kitchen.

Cops also recovered several rolls of cellophane bags and a set of digital scales which was found to have trace amounts of an off-white powder on it which also turned out to be heroin. Costello then told police there was a box of Bash in a printer box in his cellar after they found the key to the storage area on a table in his flat and a subsequent search of the area turned up 11 bags.

He was later taken to Clydebank Police Office and told officers that he was holding the mixing agent and drugs for other people but refused to tell cops who they were. Tom Brown defending said a jail sentence was inevitable but highlighted the fact Costello, whose address was given as prisoner of Low Moss, had admitted his guilt at an early opportunity and asked for leniency.

However, Sheriff Derek Livingston said it was clear the drugs found were “entirely for commercial purposes”.

He also pointed out the fact this was Costello’s second conviction for dealing Class A drugs and jailed him for 36 months.