https://www.bankofengland.co.uk/quarterly-bulletin/1990/q4/the-exchange-rate-mechanism-of-the-european-monetary-system
The exchange rate mechanism of the European monetary system | Bank of England
On Monday 8 October sterling joined the exchange rate mechanism of the European monetary system with a central rate of 0.696904 against the ECU and a bilateral...
exchange rate mechanismeuropean monetary systembankengland