Big Bang propelled the Square Mile past Wall Street to make it the world’s pre-eminent financial centre in the 1990s and 2000s. Now the City is having to fight to hold on to its leadership position even in Europe. The decision this month by Wise, the money transfer fintech giant, to switch its primary share listing from London to America, was hugely damaging symbolically. But, sadly, it was also no great surprise, following similar moves by the likes of plant hire company Ashtead and online gambling company Flutter.