Six years after Brexit, Britain and the EU face "the same challenges" and would benefit from working closer together in areas of common interest, Chris Hayward, policy chairman at the City of London Corporation, which represents the UK's financial services sector, told AFP.

Among them is defence, where Britain needed to invest more in its "European allies", Hayward said.

Facing an aggressive Russia and to reduce dependence on the US, the European Union has launched a raft of initiatives aimed at raising up to 800 billion euros ($930 billion) to help member countries bolster their military apparatus.

British banks could participate in the effort, Hayward said.

"Now that we are not going to be able to rely as heavily on the United States to fund NATO, we need to collaborate across Europe much more on financing our defence plans," Hayward said.

Sustainability, green finance and start-up development were other areas where London, with its vast capital markets and status as a global financial centre, could work with Brussels.

"We face, Europe and the UK, the same challenges. We both have low growth, very low growth. That needs to be tackled," Hayward said.

In this light, he welcomed British Prime Minister Keir Starmer's bid to reset relations with the 27-country bloc.

"We're not suggesting some sort of backdoor entry back into the EU. Absolutely not. Just where we have alignment, where we already have alignment, we want to strengthen that relationship," he said.