Last year’s disastrous wheat crop is continuing to take its toll on British wheat sourcing pledges, with McVitie’s Digestives set to start using imported wheat.

Currently, plain McVitie’s Digestives carry a Union Flag logo and the wording “100% British Wheat - Great British Taste’ - but owner United Biscuits is expecting to have to switch to a blend containing imported wheat in the coming months.

The company said it tried to use as much British wheat as possible in McVitie’s and other branded biscuits. “However the British weather, and consequently crop yields, are variable so we have arrangements to blend in wheat from other sources to maintain the high quality of our products,” added a spokesman.

Some British biscuit suppliers have been hit particularly hard by the low yield and poor quality of last year’s wheat as they use a soft wheat grown in small quantities outside the UK.

“Soft wheat makes a very soft flour that is brilliant for biscuits but we are one of the few places that grow it - so it’s not easy to get more,” said Michael Marriage, MD of organic flour supplier Doves Farm.

Other big brands forced to renege on 100%-British sourcing pledges include Hovis and Weetabix Minis.