Last year has been officially named as the hottest year on record.
Climate experts at the US National Oceanic and Atmospheric Administration confirmed 2014 had the highest global temperatures.
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Mr Cameron, who went to the same school as Mr Johnson, said he knows how fit his friend is from "facing him on the tennis court".
Mr Gove is self-isolating after a family member began experiencing symptoms of coronavirus.
A carer had just completed a £60 shopping trip for a vulnerable resident, which was stolen along with her car.