Sainsbury's has pledged to double its sales of wines that are 10.5% abv and ­below and cut the average ­alcohol content of its own-label wine and beer.

Sainsbury's made the pledge this week in its 20 by 20 Sustainability Plan, setting out 20 targets for its products, community work and employees to reach by 2020. In January, the retailer will offer a 25% discount on its 'lighter' ­alcohol wines to support the initiative.

Category manager Andy Phelps said the vow posed technical challenges, but was "the right thing to do".