As the London Stock Exchange is the most closely watched market in Europe it is well worth it to both follow and trade the FTSE 100. Often the index will follow moves made by the British Pound as well, since roughly 80% of the companies are multi-nationals that benefit from a weak Pound. This can help inform trades and forecast the direction the index will take, It can also be a good choice to trade the FTSE 100 when its major constituents report good news.