As the U.K. awaits a decision on its exit from the European Union, uncertainty and fears about London's standing as a financial centre remain the major concerns for U.K. and EU law firms and their clients.

A straw poll of top partners found that amid the recurrent theme of crippling uncertainty, partners' biggest overarching concern was the possibility that London will cease to generate the same level of work for commercial law firms as it has done in the past.

Freshfields Bruckhaus Deringer head of financial institutions regulatory partner James Smethurst said that while there are short-term complications, the long-term worry is Brexit's effect on the wider economy. He said: "If you've got non-financial businesses trading with the EU, then they're going to face an impact from Brexit. And then there's a knock-on impact on the financial sector if companies have difficulty financing the loans."

"In uncertain times people tend to sit on their hands"

Hogan Lovells corporate partner Daniel Simons said: "A lot of the work that I do focuses on the London market – in particular IPOs and secondary fundraisings – and neither market volatility nor uncertainty bodes well for that. If we see a consistent trend of large European companies looking to do IPOs in other jurisdictions, it could be the start of a slippery slope for us."