A new eco-friendly coffee backed by fashion designer Vivienne Westwood has come up with a promotion urging shoppers to "buy one get one tree free".

Environmental charity Cool Earth launched its eponymous coffee (£2.99/100g) this week, backed by Dame Vivienne Westwood. For every jar sold, an Amazonian tree at risk of being logged will be saved, which will "lock in" at least one tonne of CO2, the eco-charity says.

The coffee, which is rolling into 600 Tesco stores, also comes in 500g tubs that each protect five trees.