For U.K. pubgoers, the biggest choices are generally straightforward: beer or whisky, draft or bottle, pint or half.

But now, beer-drinking Brits face a new and increasingly frequent quandary — to tip or not to tip.

Some of the country’s biggest pub chains are asking guests to top up the tab with a gratuity of 10% or more, making for awkward moments at the public house, an institution whose age-old appeal is ingrained in the reliable fabric of British tradition.