Financial services litigation and compliance expert Michael Ruck of Pinsent Masons, the law firm behind Out-Law.com, said anti-money laundering requirements and pressure exerted from competition regulators set competing agendas that banks must balance.

"Banks are under increasing scrutiny from the likes of the Financial Conduct Authority and Serious Fraud Office with regards the steps they are taking to prevent their services being used for money laundering or other financial crime," Ruck said. "This has meant that many banks are adopting a cautious approach when deciding whether to provide banking facilities to financial technology businesses, such as crowdfunding platforms. A particular worry they have is whether they can rely on the checks the fintech companies carry out on their users."

"However, separately banks are under pressure from competition regulators. Those regulators are keen to promote competition in the banking sector and have said they will take a dim view of any anti-competitive barriers banks put in the way of new entrants to their market. This might be said to include crowdfunding platforms that provide alternative financing and operate in the lending market," he said.

Ruck was commenting after the Times reported that some crowdfunding platforms have found problems obtaining bank facilities, including access to account services. The FCA said that banks' interpretation of money laundering rules might be a reason why some are reluctant to provide banking facilities to financial technology companies.

“We are aware that innovator businesses are experiencing difficulties in obtaining access to bank accounts," the FCA said. "Financial institutions' interpretation of the anti-money-laundering regime and perception of regulatory expectations may be a factor in this."

The FCA said that it was "considering what more we could do in this field".

Ruck said banks are particularly wary about their anti-money laundering obligations after the FCA identified failings with how small banks are managing "money laundering and sanctions risk" in November last year.

He said that the FCA will be restricted in what it can do to help financial technology companies access bank services without weakening the anti-money laundering regime.

"EU anti-money laundering rules do allow banks to rely on customer due diligence checks carried out by third parties, but at the same time do not exempt banks from liability for any weaknesses in those policies and procedures," Ruck said. "The FCA is unlikely to allow banks to absolve themselves of liability in the event that the proceeds of crime are found passing through their systems, for example, just because they had relied on third party checks on customers and transactions."

Ruck said that banks must ensure that their anti-money laundering controls are sufficiently strong to comply with their legal obligations and to avoid commercial risks, such as being seen as a business that harbours illicit activity. Equally, banks must be able to justify decisions to block challenger businesses from using their facilities to ensure compliance with competition laws and avoid gaining a reputation as a company that is not open for business, he said.