STORY: The event was hosted by the RMT union which has been at the heart of strikes that have crippled Britain's transport network in recent months as workers demand better pay and conditions to counter the impact of soaring energy price-driven inflation.

Sanders, a democratic socialist whose progressive campaigning helped push the U.S. Democratic Party agenda sharply to the left, ran to be U.S. president in 2020 but ultimately lost out on the party nomination to eventual election winner Joe Biden.