According to new papers released under the Freedom of Information Act, the Treasury's "best estimate" of the cost of intervention to defend the pound during Britain's doomed attempt to stay in the European Exchange Rate Mechanism in 1992 was $4.9 bn (£3.3 bn). This is arrived at by comparing what the value of the reserves would have been if there had been no intervention on Black Wednesday or in the run-up to it, compared with the actual value of the reserves at subsequent dates. The actual loss