Brexit threatening London's place as banking hub

London

FROM a skyscraper in Canary Wharf, the once-bustling cluster of docks transformed into a global banking centre, traders at Citigroup's regional headquarters move unfathomable sums of money around the planet. They are exploiting London's unrivalled connections to the intricate plumbing of the international financial system.

Now, the flow of money is in doubt, imperilling London's fortunes.

Many of the transactions Citigroup oversees here are dependent on Britain's inclusion in the European Union (EU). Italian banks tap London's vast pools of money to …