A trademarked wholehead lettuce called One-cut Salanova, which is easy to prepare with one cut across the base, is being stocked for the first time by M&S and Waitrose.

Developed by Rijkzwan in the Netherlands from a Butterhead variety, it was chosen from a chance seedling and is already popular on the Continent.

The Salanova is shaped like a rose with uniform leaves and comes in three varieties - green leaf, a red/green variation sweeter than other pigmented types, and a sweet red/brown variety.

The UK crop was successfully trialled on the Fens by G's Marketing last year, which is now looking at the possibility of production on its Spanish farms to provide year-round continuity when the English season closes in September.

Antonia Galloway, G's marketing officer, said: "As far as we're aware, we're the only outdoor grower of Salanova in the UK."