* Business * Lehman Brothers Lehman downfall triggered by mix-up between London and Washington

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• Larry Elliott and Jill Treanor
• guardian.co.uk, Thursday 3 September 2009 18.17 BST

A breakdown in communications at the highest level between the US and the UK led to the shock collapse of the investment bank Lehman Brothers in September last year, a Guardian/Observer investigation has revealed.

The downfall of Lehman, which triggered the biggest banking crisis since the Great Depression, came after a rescue bid by the high street bank Barclays failed to materialise.

In London, the Treasury, the Bank of England and the Financial Services Authority all believed that the US government would step in with a financial guarantee for the troubled Wall Street bank. The tripartite authorities insist that they always made it clear to the Americans that a possible bid from Barclays could go ahead only if sweetened by US money.