He was joined by President Ali Bongo Ondimba of Gabon at the south-west London venue as they met experts who have rediscovered a coffee species resilient to higher temperatures.

       It is capable of protecting the livelihoods of 100 million farmers across the world and the associated global multibillion pound business.

       Botanists at Kew's Herbarium helped to rediscover the Coffea Stenophylla species, which grows in Sierra Leone. A study found the plant, which grows well in shade - so is good for forest preservation and capturing carbon - can tolerate much hotter temperatures.