Markets twitchy as socialist Corbyn set to lead Labour

By Jemima Kelly LONDON (Reuters) - Markets usually pay little heed to opposition party leadership elections, but the emergence of hard-left Eurosceptic Jeremy Corbyn as the frontrunner to head Britain's Labour party is making investors twitchy. The key concern is that a victory for Corbyn, even if he were never elected prime minister, could increase the risk of "Brexit" -- a British vote to leave the European Union in a referendum pledged by the end of 2017 but which may come as soon as next Jun