LONDON (Reuters) – Top British fashion designers Vivienne Westwood and Katharine Hamnett joined bee campaigners outside the Houses of Parliament in London on Friday to urge the government to support a proposed European Union (EU) ban on pesticides which harm bees. Britain is currently one of a group of countries blocking attempts to introduce a Europe-wide ban on the world's most widely used insecticides, neonicotinoids, arguing their impact on bees is unclear. A vote takes place in Brussels on April 29 on whether to ban the poisons on flowering crops. …