“Dave” - who wishes to guard his real identity - is quite frank about what he was driven to by his addiction to heroin. The all-consuming need to find �10 for his next fix soon exhausted possibilities such as borrowing from family and friends and selling personal possessions.

“Dave” - who wishes to guard his real identity - is quite frank about what he was driven to by his addiction to heroin.

The all-consuming need to find �10 for his next fix soon exhausted possibilities such as borrowing from family and friends and selling personal possessions.

Stealing from his home town shops was the next resort, and one that he matter-of-factly describes as “taking candy from a baby”.

He knew the layout of every shop in Gorleston high street, the ones that had store detectives or cameras, those with soft-target aisles and displays - even the ones with alert managers.

He is quite candid about the fact that until he cured his drug habit six years ago, he would sometimes plunder the shops three or four times a day, taking everything from meat to clothes that he would sell for up to �150.

Town centre police constable Jason Howell admits that Dave used to be one of the town's most prolific offenders, but since arresting him for the last time, he has watched him go straight, getting a job and steady relationship.

Now the pair has formed an unlikely crime-busting partnership, PC Howell using Dave's shoplifting know-how to produce a pioneering crime prevention survey for the high street.

Prompted by the safer neighbourhood team's pre-Christmas crackdown on shop crime, the pair visited every shop and Dave advised PC Howell about weak spots and soft targets. It has resulted in a document offering both practical general advice as well as specific tips for all the main shops.

In the introduction to the survey - which has been well-received by shopkeepers - Dave advises that early morning is the time often chosen by habitual thieves when there are fewer staff and they are less alert.

“Saturday mornings were always good for me; staff seemed to have sleep in their eyes from a hectic or late night before,” he says.

“It was also very dependent on particular store managers. If it was one in particular I knew was very alert, then it would deter me.”

He indicates that meat, either frozen or fresh, was one of the best items to steal and sell, while chocolates and toiletries were good in the run-up to Christmas.

Dave's practical advice includes suggestions such as lowering shelving to reduce places of concealment, keeping expensive items nearer to checkouts and securing staff areas.

He urges shop staff to look out for bikes, which are used for a quick escape, bulky clothes and large 'bags for life' that could be foil lined to thwart alarms.

One well-known national retailer is branded the easiest to steal from in Gorleston because of tall shelving and staff at the back of the shop, while another “has a lot of clothing pillars to hide behind”.

He describes Morrison's, formerly Somerfield, as the most difficult to steal from due to its store detectives and CCTV - “the best deterrents” - awkward layout, well-placed checkouts and security tagging.

PC Howell said: “Until I did this survey, I had the idea that shop thieves were really not that clever because their crime was drug-related and they were probably spaced out. But in fact they often pre-plan their day, shop to order and think on their feet.”

He cited one example from Dave's past when he used to hide items of clothing above the ceiling tiles of a particular shop changing room to collect on another day when there were fewer people about.

Steve McKechnie, manager of Iceland, said the survey had given him a valuable new insight. As a result, he had moved high-value meat from the first aisle nearest the door and had also made staff aware that early morning was a critical time.