By Kanishka Singh (Reuters) – The former leader of a Hong Kong pro-independence group, who was sentenced in 2021 to prison under a national security law imposed by China, said on Thursday he had fled to Britain and formally applied for political asylum. WHY IT’S IMPORTANT In November 2021, Tony Chung, who was then 20, was sentenced to 43 months in prison for trying to separate the city from China, and for money laundering. Chung was charged with secession under the sweeping national security law in 2020 and denied bail. Beijing imposed the national security law on the Asian financial hub in 20…