When Tate Liverpool opened in 1988, it was England's first gallery of modern art, but its origins were mired in the politics of the decade. It was part of the government's response to the Toxteth riots and was not universally welcomed. Now, as it celebrates its 30th anniversary, comedian and former art student Alexei Sayle assesses its impact on his home city and meets Lord Heseltine, the politician who was made minister for Liverpool to try to solve the city's economic and social problems in the 80s.