Waitrose is changing a free tea and coffee deal in its cafes after customers lingered at tables without buying anything else.

The grocer said the switch in policy was a reminder to myWaitrose card holders of the “etiquette” involved in the arrangement, The Guardian reported.

From February 9, cardholders must buy a “treat” - such as a sandwich, cake or biscuit – if they want a free hot drink in a cafe.

In an email to scheme members Waitrose said: “This change will enable us to continue to offer our customers the enjoyable service they expect.”

The change will not impact customers who want to take away a free hot drink.

A Waitrose spokeswoman said: “Most people understand that if they want to sit in the cafe and enjoy their hot drink, they buy something to go with it.”

The change is designed to be fair to shoppers who intend to buy a meal or a snack in cafes who find that all the seats are occupied by non-paying customers.

The spokeswoman dismissed the suggestion that the change was prompted by a “middle-class backlash” from customers upset that the stores were attracting less well-off shoppers.