You have to admire some people for their sheer bloody-mindedness: when Colin Roberts and Mandy Coghlan discovered their cannabis farm had been stolen, they picked up the phone and called 999.

When the police in Stoke-on-Trent turned up to arrest Roberts for producing the drug, his partner threatened officers with an air pistol.

Astonishingly, they ended up in court, even though they were the victims of the piece.

This may be the time to reprise Norfolk police's advice to the public on how to spot the signs that a cannabis factory is operating in a house in your neighbourhood.

They include:

•The curtains at the property are constantly closed.

•There is a lot of noise when someone moves into a property, but afterwards no one seems to be living there.

•There is a strange smell.

These indications are similar, although subtly different, to spotting the signs you might be living next door to a murderer that 'keeps himself to himself', medical students or a corpse.

Other signs that you might be living next door to a cannabis factory are as follows:

•You live next door to a 'dream' neighbour who is silent, doesn't take your parking space and hasn't noticed that you always fill up their recycling bins.

•Your teenager children shun standing in desolate bus shelters drinking lurid alcopops and spitting at strangers in order to sit in your garden, inhaling.

•The birds on top of the chimney stack next door are singing Bob Marley's One Love.

•You keep meaning to ask the nice, laidback man you saw moving in 10 months ago for the secret to his green-fingered success: you kill houseplants in a week, the ones you can see in his back bedroom are six feet tall.

Roberts and Coghlan were given 12-month prison sentences, suspended for two years.

Their cannabis is still missing in action, presumed smoked.