A GREEN-FINGERED enthusiast has been left bewildered at what he believes to be a cannabis plant growing in his back garden.

James Burns, 70, of Southwick, says the 18-inch tall plant has been steadily growing since he filled a flower pot with compost three months ago.

He bought the compost from B&Q in Shoreham, though he said he cannot be certain the plant's seed was in the bag.

Mr Burns said: "I bought three bags of compost a few months back and the plant has appeared since then. I think it might have come from the compost because never before in my life has a cannabis or hemp seed ever dropped in my garden.

"I can't prove it came from the compost but it's coincidental that we got the three bags and put it in some troughs and containers and the plant started growing out of a pot by itself.

"It looks like a cannabis plant and when you squeeze the leaves it has a smell too."

In September last year a pensioner from Exmouth unwittingly grew a 5ft tall cannabis plant from a pack of bird seeds.

Experts say it is common for bird seen to contain a variety of plant seeds - including cannabis - and they can find their way to people's gardens in faeces.

Mr Burns said his friends and family thought his plant was "hilarious".

He added: "They joke that we're starting up a cultivation business. I've never really seen a cannabis plant before but I saw one on television and thought it looked like it was from the same family as the one in my garden.

"I've put it behind the greenhouse where it's been growing quite happily. But we'll just let it grow and die. There's no point keeping it for us - it's of no use to me."

Tim Clapp, trained botanist and horticulture and garden care lead buyer at B&Q said it was not the first time someone had "accidentally grown cannabis" in the UK.

He said: "Commonly bought bird seed contains a huge variety of plant seed and cannabis has been known to grow from that.

"The bird seed may drop into flower beds by accident or can be transferred in the bird’s faeces.

"Anyone who suspects that they are in possession of an illegal drug, such as cannabis, should follow police guidelines to either destroy it or take it to a police station.”