Insiders from London's financial institutions warned that stress tests on European banks could be useless and hinder market confidence. "I don't think it is going to work," said Jacques Cailloux, Europe economist at Royal Bank of Scotland. "These stress tests are not rigorous enough. Investors are already pricing in a 50% 'haircut' on some Greek bonds so this has to be included, and perhaps 30% for Spain. We have had a complete failure of communication by the euro zone over recent months, with 16 countries all saying different things, and there is a very high chance of another failure this time."