LONDON (Reuters) - The UK's top share index slid on Wednesday, under pressure from a bounce in the pound on the back of remarks from the European Union's chief negotiator Michel Barnier, who offered Britain close ties after Brexit.The blue chip FTSE 100 index ended the session down 0.7 percent at 7,563.21 points, underperforming a broadly positive European equity markets.The EU's Barnier said that the bloc was prepared to offer Britain a partnership, though no "single market a la carte", which..