Britain's 'first Brexit' was, plausibly, Britain's 'Black Wednesday' withdrawal from Europe's exchange rate mechanism (the forerunner of economic and monetary union) on 16 September 1992.
There had been antecedents. Some might date the first schism with Europe to the departure of Roman legions in 400AD or Henry VIII's 1530s break with the Church of Rome. There may be parallels, too, with the retreat of the British Expeditionary Force from Dunkirk in 1940. Yet, through whatever lens it is viewed, the chronicle of Britain's entanglement with the ERM represents a major landmark in the UK's European history.
Having advanced separately alongside the creation of European institutions and the march of economic integration in the 1950s and 1960s, Britain, by entering the European Community in 1973, established significant convergence with the continent. However, sterling and the British economy thereafter developed on a semi-detached path. By joining the ERM in October 1990, Britain, it seemed, had become a full European participant.
Then came the traumatic exit - a reversion to the UK's traditional distance from the European core. The experience of 16 September contributed to the discredit and later electoral defeat of Prime Minister John Major and to the Labour government's reluctance to join the euro when Tony Blair took power in 1997. A logical next step was the June 2016 referendum rejection of EU membership, marking a return to the separation of the 1950s and 1960s.
In 1990 Britain signed up to a central element of western European unity just at the time when it was changing force and character in a way that no one - certainly not the British with their island ways - could even recognise, let alone understand. With the fall of the Berlin Wall and the dissolution of the Soviet empire, the circumstances that had drawn western Europe together after 1945 were starting to lose traction.