For each tin sold, the charity will protect five trees in the Amazon which would otherwise have fallen victim to loggers. Under the £375,000 contract, this equates to around 300,000 trees covering an area four times the size of London's Hyde Park.

It is also estimated that thanks to the MoD's purchase of the 100 per cent Rainforest Alliance Certified Brazilian coffee beans, around 410,526 tonnes of carbon dioxide will be offset.

Captain Jeremy Rigby RN, defence food team leader at the MOD's Defence Equipment and Support organisation said: "This contract is an example of how we have been able to secure a quality brand of coffee for our troops, which is value for money to the taxpayer and also furthers our commitment to supporting wider green issues.

"I am pleased that through this contract we will be directly supporting Cool Earth's valiant effort to safeguard our endangered rainforests."

The contract goes live this month and will run for an initial 12 months with an option to extend.

Founded in 2007, Cool Earth is an environmental charity dedicated to the protection of the rainforest in order to help combat climate change. All of their projects are community-led, putting local people in charge.

The coffee itself is produced and manufactured by Surrey-based FFI (Fine Foods International), one of the UK's leading suppliers of instant coffee, roast and ground coffee and hot beverages.