The north east is leading the way in cracking down on sales of alcohol to under-age drinkers, according to
figures from test purchasing company Serve Legal.
The region's retailers achieved a pass rate of 87% after being anonymously visited by teenagers.
Sales staff needed to ask to see a customer's ID if they thought the purchaser was 21 or younger.
The next best -performing regions were the Midlands (80%), south central (75%), London (72%) and Scotland (64%). At the other end of the scale, the worst -performing regions were Northern Ireland (8%), the south west (57%) and Wales (58%).
Supermarkets achieved a pass rate of 72%, while the convenience sector had a pass rate of 63%.
James Lowman, chief executive of the Association of Convenience Stores, said: "It's encouraging that the pass rates are improving but there's still
way to go.
"Even if you are very good [about asking for ID] you could still be in trouble -
you have to be outstanding every time."
Serve Legal director Charlie Mowat said that all retailers should be extra vigilant in the run-up to Christmas.
He said: "If you are let down by your staff and are caught serving alcohol to anyone under-age, you could lose your licence and independent retailers could lose their livelihood.
"Of all the issues currently facing retailers, the government's determination to eradicate under-age drinking and sales to minors, and close or penalise problem premises, is perhaps the biggest threat."
Serve Legal is employed by Asda, Waitrose, Thresher Group, Londis and Spar. A nationwide team of 18 and
19-year-old testers carried out more than 4,0 00 visits to supermarkets, convenience stores and off-licences between July and September.