The chairmen of Britain’s biggest banks began their defense of London as the world’s trading hub after the Brexit vote wiped $45 billion from the value of their companies and raised the chances that financial jobs will move to other cities.

Barclays Plc Chief Executive Officer Jes Staley said concern about earnings, rather than capital or liquidity, has caused the “significant” dip in the bank’s share price since the U.K. voted to leave the European Union.

The two front-runners to succeed David Cameron as prime minister set the U.K. on a collision course with European Union leaders after both said they were in no hurry to trigger the mechanism that would start Britain’s withdrawal from the bloc.