Thousands of people are marching in cities across the UK to mark Cannabis Liberation Day. The Million Marijuana March is a worldwide event involving people taking to the streets in nearly 200 cities across the globe. According to the organisation's website, marches are taking place in London, Manchester, Birmingham, Liverpool, Edinburgh, Hull, Sheffield and Stafford. In London the march, entitled Dance on the Grave of Cannabis Prohibition, will go from Kennington Park to Brockwell Park, in south London, where a festival is being held featuring live music, a speakers tent and food stalls. Across the world marches are taking place...