Sainsbury's aims to double British-sourced food sales by 2020

The target is part of the grocer’s new £1bn sustainability plan – The Sainsbury’s 20 by 20 Sustainability Plan - which sets out 20 goals it intends to reach by 2020.

The grocer currently spends over £4bn each year with UK suppliers.

As part of the plan, the supermarket is also planning to increase the sales of fair trade products to £1bn by that date.

The grocer is also aiming to cut carbon emissions by 30% by that date and is adopting carbon-saving technologies in new and existing stores to drive down energy usage.

It also intends to create 50,000 new jobs in the UK by 2020.

Sainsbury’s chief executive Justin King, said: “Given the scale of our business, we believe these 20 commitments represent the most ambitious sustainability targets in our industry.

“If we are to meet the sustainability challenges that lie ahead, it is important that companies such as Sainsbury’s invest in the future right now.

Prime minister David Cameron said of the plan: “It is a great example of the principles of Every Business Commits - helping to create jobs and growth whilst also tackling our shared social and environmental challenges, investing in their workforce and in our communities, and building a bigger, stronger society.”