The British Beer and Pub Association compiled the rules last month to curb promotions such as happy hours and cut-price drinks.

But many places in the county are apparently ignoring the guidelines.

Spokesman Mark Hastings said the association can only ensure its own member firms tow the line.

'Industry benchmark'

He said: "There are a lot of other pubs and clubs and bars and restaurants and other venues that aren't part of our membership.

"And that requires the help of licensing authorities, police and other local agencies to ensure that these standards that we have set become the benchmark for all the industry."

Robin Maplestone, the manager of Yates' in Lincoln, said the solution was to crack down on the price war among rival bars.

He said: "Drinks promotions will continue, and at the end of the day I'm like any other bar around Lincoln - I want everybody in my bar.

"What we need to do is to come up with some kind of formula of some sort of a minimum price banding and all the bars to follow suit.