Dundee-based wholesaler and Spar retailer CJ Lang is introducing a Challenge 25 policy in a bid to prevent underage sales of alcohol.

CJ Lang currently asks its retailers to demand ID from anyone staff believe to be under 21. It is set to increase this threshold to 25 from 1 March in a switch that mirrors that of fellow Scottish convenience operators David Sands and Botterills.

CJ Lang also recently put its 200 staff though training covering the sale of alcohol, and redrafted its company procedures for sales of licensed products.

In the run-up to Christmas, executives had worked in stores - often until closing time - to see at first hand the difficulties faced by staff when refusing to serve the underage.

"Our efforts in relation to the prevention of underage drinking did not start with test purchasing and its penalties," said CJ Lang chief executive David Walker. "We have, for years, been trying to protect staff from mistakes they can make relatively easily."