By Jessica Frank-Keyes The former Tory net zero tsar Chris Skidmore has revealed he will back Labour at the July 4 general election. Skidmore, who quit as a Conservative MP in January over government plans for new oil and gas licences, laid into the Prime Minister over what he called “siding with climate deniers”. His resignation triggered a by-election in Kingswood, near Bristol, which Labour won. It makes the former minister the biggest Tory name so far to lend his backing to Sir Keir Starmer’s party, as Rishi Sunak leads his party into the final two weeks of the campaign. Writing in the Gua…