Implicit in the decision to return to the gold standard at the exchange rate of $4.86 in 1925 was the assumption that it would benefit both the City of London and the government. The City would again operate in a currency of unsurpassed prestige, backed by gold and unique among major European currencies in retaining its prewar exchange rate. Holders of sterling and sterling-denominated securities would know that under the gold standard the Bank of England was obliged to exchange sterling for gold at a statutory rate (one standard ounce of gold = 77s 10½d) and to defend the rate through every means available to it, including adjustment of bank rate and other interest rates. The gold standard also promised to constrain politicians from interfering in the monetary and financial system, which under gold would operate according to supposedly automatic rules. In the event that politicians succumbed to the temptation to over-tax or over-spend, the gold standard would bring them up short when their actions reduced the country's international competitiveness, weakened its balance of trade and forced the Bank of England to raise interest rates. In fact, the gold standard had an even broader appeal to the merchants, brokers, insurance underwriters, shipowners, financiers and bankers of the City, which was that, in theory at least, it made redundant other restraints upon trade and finance.