All four of the UK's big banks are on a list to be 'stress-tested' by the European Union to measure their ability to withstand another major financial shock in future.HSBC, Royal Bank of Scotland, Lloyds and Barclays are among 91 banks selected by the EU to face scrutiny, a much greater number than originally expected. All other major European banks are also included, though the main focus of the tests seems to be on the smaller regional banks in Spain, Greece and Germany, where concerns over debt defaults have been greatest.The EU's Committee of European Banking Supervisors said collectively the banks represented 65% of the European Union's banking sector. They account for at least 50% of the banking sector in their respective countries.The 91 banks will be assessed first on the basis that economic growth is 3% below forecasts in 2010 and 2011 and then a deterioration of market conditions similar to the May where fears of sovereign debt defaults swept through markets.The UK financial regulator, the Financial Services Authority, has already tested the UK banks using its own measures. These were tougher the ones set out yesterday and the regulator is said to be 100% confident UK banks will pass the European checks.