The gold standard was suspended at the outbreak of the war in 1914, with Bank of England and Treasury notes becoming legal tender. Before World War I, the United Kingdom had one of the world's strongest economies, holding 40% of the world's overseas investments. But after the end of the war, the country was indebted: Britain owed £850 million (£ as of 2015) with interest costing the country some 40% of all government spending. To try to resume stability, a version of the gold standard was reintroduced in 1925, under which the currency was fixed to gold at its pre-war peg, but one could only exchange currency for gold bullion, not for coins. This was abandoned on 21 September 1931, during the Great Depression, and sterling suffered an initial devaluation of some 25%.