Retailers have urged local authorities to work more closely with the trade to tackle attempts by underage teens to buy alcohol, after a series of failed test purchases over the Christmas period.

New alcohol test-purchasing schemes launched ahead of the Christmas holidays caught a number of retailers off-guard and resulted in £80 on-the-spot fines for staff as well as possibility of revoked licences for so-called 'persistent' offenders. The failures came as PM Gordon Brown reiterated his plans to focus the government's attention on retailer responsibility.

In the Lincolnshire town of Louth, close to a third of stores tested sold alcohol to underage teenagers. In and around Reading, Berkshire, just under a quarter of stores targeted failed tests, including a Tesco Express store in Caversham, which previously failed a test in 2006. On Teesside some 20% of retailers sold to underage customers, while Dumfries and Galloway police reported failed tests in three out of seven businesses targeted in Annan.

A number of retailers caught selling to teenagers accepted their punishment, but called for greater team work to help deal with the problem. One told Convenience Store: "Trading Standards are always targeting their campaigns at times of the year when retailers are most vulnerable. They need to work more with retailers." Another said he believed his staff had been "duped" and was disappointed local press had been informed of the failure before he had.

While the Association of Convenience Stores (ACS) said it would wait to see the full results of the Christmas crackdown, it pointed to the improving performance of the off trade in national figures released last year. Summer tests revealed that from 9,000 tests, failure rates were 14% in the off trade compared with 18% in pubs and clubs.

It also welcomed the month-long national police operation from October which resulted in the seizure of 3,700 litres of alcohol from underage drinkers. ACS chief executive James Lowman said: "It's absolutely right that police should take action directly against young people who drink when underage. ACS advocates a complete approach to tackling underage drinking and we have been talking to ministers urging interventions like this to be used more widely."