Waitrose is to "refine" its offer of free tea and coffee for members of its loyalty card scheme by handing out cups after they have paid for their shopping.

Currently, myWaitrose card holders can collect their hot beverage as they enter the supermarket and enjoy it as they shop in the aisles.

But an email sent to them today says they will be asked to confirm they have made a purchase before picking up their free drink from April 3.

A spokesman said shoppers will be given a cup as they go through the checkout.

There will continue to be no minimum spend requirement.

Waitrose said the change was "just a refinement" to the offer.

The email to customers says: "Our myWaitrose free tea and coffee offer is one of the ways we thank our customers for shopping with us - and we want all our customers to be able to enjoy a free hot drink when they shop with us in our branches.

"From 3 April, we'll simply be asking myWaitrose members to make a purchase before collecting their cup at the checkout.

"We would like to thank you in advance for your understanding."

In 2015 Waitrose scrapped a tea and coffee free-for-all which allowed myWaitrose members to enjoy a hot drink for nothing in its cafes even if they had bought nothing else.

Members of the scheme were told that if they wished to enjoy a free tea or coffee in one of its cafes they must also purchase a "treat" such as "a sandwich, cake, biscuit or piece of fruit".

"This change will enable us to continue to offer our customers the enjoyable service they expect," the email said.

The store brushed off the suggestion that the 2015 change was in response to reports that Waitrose was facing a middle-class backlash from customers upset that the stores were being invaded by less well-off shoppers.