Marks & Spencer is being forced to rebrand one of its biggest selling food ranges, Fuller Longer, after admitting it was in breach of EU laws on health claims.

More than 50 lines across food on the move, salads, groceries and prepared meals will be replaced from next month under the new name ‘Balanced for You’.

M&S was alerted to the breach by UK Trading Standards. The retailer said it was carrying out more research into future developments but there would be no changes to products in the short term.

“The brand is changing to bring it into line with EU law,” confirmed an M&S spokesman. “The new packaging will be in-store next month.”

M&S launched Fuller Longer in 2010, after employing weight loss experts at the Rowett Institute of Nutrition and Health at the University of Aberdeen.

The popular range ­featured food from sources such as beans, pulses and ­vegetables and was based on the idea that the right balance of proteins and carbohydrates increased satiety levels and reduced the need for snacking.