Your chance to grass up the neighbours: 'Scratch and sniff' cannabis cards to be posted to thousands of UK homes by Crimestoppers to aid police crackdown on marijuana farms

Cards come with a list of 'signs to look out', as well as a paper panel which releases a strong odour of cannabis when scratched

(Crimestoppers)

The war on drugs just took a pungent turn with the news that Crimestoppers, the independent crime-fighting charity, is sending thousands of rural homes a leaflet explaining how to recognise signs that someone nearby is running a marijuana farm.

There's been a 15 per cent increase in dope husbandry since 2011, with West Yorkshire topping the league of badass farmers (1,800 police busts between 2010 and 2012.) Appalled by the proliferation of reefer nurseries, the authorities want to persuade law-abiding rustics to, well, grass up their neighbours.

Remarkably, they are offering them scratch 'n' sniff cards, so that non-druggy householders can familiarise themselves with the pong of growing cannabis (though not burning cannabis, which is far more identifiable).

Though we approve of the use of scratch 'n' sniff cards in gardening catalogues and food magazines, we aren't sure they'll work in the crime-busting area.

How many recipients will grow to like the heady scent of cannabis sativa mingled with cardboard, and will happily light them up and inhale?

How many will use the card as an impregnated joint-roach, as one uses basil-scented oil for cooking steak? And, if we follow the logic of drug-identification, will the next stage be to issue householders with scratch 'n' sniff cards containing minute trace elements of cocaine, so that they'll be able to identify the white substance in their neighbour's bathroom and their teenage daughter's make-up case? I can see those becoming very popular…