Officers and Trading Standards representatives say of the 17 stores they visited, 12 sold drink to youngsters aged 14 to 16.

At nine of the premises, the shop assistants involved were issued with an �80 on-the-spot fine.

Investigations into the licensees of the shops involved are now under way - they could face fines of up to �1,000.

Somerset County Councillor Hazel Prior-Sankey said: "It is greatly disappointing that this survey suggests more businesses will sell alcohol to children than will refuse.

"I hope the reality of the �80 fines issued to the sellers will focus attention and enable us to move towards a 'no ID, no sale' culture."