Charles Wells, the Bedford-based brewer and pub operator, has raised concerns about possible practical and safety issues of complying with a Responsibility Deal pledge to provide alcohol unit information on all branded glassware.

On 1 January Charles Wells pledged to provide unit information on all its branded glassware by the end of 2013. Updating the Department of Health on its progress, Charles Wells said it was investigating the implications of the pledge “as concerns have been raised as to practicalities and safety of doing so”.

“We want to avoid a situation that could cause problems through no fault of our own - such as a licensee serving a drink in the wrong branded glass and unwittingly providing the consumer with incorrect unit guidance.

“We are following up these concerns as a matter of urgency and seeking advice on best practice from other suppliers.”

The target was set under pledge A2 of the Responsibility Deal Alcohol Network, which commits firms to improve awareness of alcohol units in the on-trade.

Heineken UK said it introduced more than 16m unit-branded glasses by the end of 2012, exceeding its initial commitment of 11m. The company said it provided its leased pub arm, Star Pubs & Bars, with unit awareness campaign material in 2012.

Mitchells & Butlers said the “vast majority” of its businesses provided customers with unit information and ABV details on drinks menus. Marston’s said all its managed sites have either posters, tent cards or drip mats, with unit information, and Fuller’s has sent 50 unit information leaflets to every one of its pubs.

Cheshire-based Frederic Robinson said: “All our pump clips now have units per pint on the pumpclip in a prominent form. This has been well received by all our customers. ABV continues to be also shown.”