Hammond sought to allay fears by outlining a three-step plan to securing the industry. This involves establishing new regulatory guidelines for businesses; conducting risk management; and reassuring businesses that the new framework will be permanent.

“Avoiding fragmentation of financial services is a huge prize for the economies of Europe.”

“First, we will need a new process for establishing regulatory requirements for cross-border business between the UK and EU. It must be evidence-based, symmetrical, and transparent. And it must reflect international standards.

“Second, cooperation arrangements must be reciprocal, reliable, and prioritise financial stability. Crucially they must enable timely and coordinated risk management on both sides.

“Third, these arrangements must be permanent and reliable for the businesses regulated under these regimes.

Hammond’s comments on the financial services industry came amid wider calls for a transition period for all businesses.

“We’ll almost certainly need an implementation period, outside the (EU’s) customs union itself, but with current customs border arrangements remaining in place, until new long-term arrangements are up and running.”

Hammond was initially due to make his Mansion House address last Thursday but it was delayed in the wake of a fire at a tower block in west London.

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