Pubs are missing out on over half a million legitimate customers because they are "confused" as to what are acceptable forms of identification, according to PASS.
A survey by PASS, the firm that issues the Citizen Cards, found that 47% of card holders have had their card refused. It added that 97% of the refusals "occur in the on-trade".
PASS card director Kate Winstanley said: "With 1.5 million PASS cards in circulation, this data suggests that well over half a million legitimate customers with PASS cards have been turned away from UK pubs, clubs and bars."
"There are 1.6 million people aged 18 and 19 in the UK and a third of these have neither a driving license nor passport — that is over half a million people.
"It makes enormous business sense for pubs to ensure that these young adults can rely on the robust proof of age that PASS hologramed cards represent, so as not to lose out on their custom."
BBPA chief executive Brigid Simmonds said "As the most sociable place to enjoy a drink, pubs should be giving every legitimate customer the warmest possible welcome — not turning them away."