By Sonia Elks / Thomson Reuters Foundation, LONDONAs Britain left the EU on Friday and starts work to rewrite its relationship with the bloc and quickly strike new global trade deals, some fear Brexit might undercut a similarly demanding key pledge to reach net-zero carbon emissions by 2050. London cannot allow tricky trade and foreign policy negotiations to delay climate action if the 2050 net-zero target is to be met, said Mike Thompson, director of analysis at the Committee on Climate Change (CCC), which advises the government. “This is not about making a few tweaks at the edges of what we are doing,” he told the Thomson Reuters Foundation on the shift required to meet the net-zero goal. In the middle of the messy divorce, then-British prime minister Theresa May announced the 2050 net-zero target, which was passed into law. Former top government scientist David King has described Brexit as an “enormous distraction” from meeting climate goals.