Jerry del Missier, co-chief executive of Barclays Capital and chairman of the Wall Street lobby group Sifma, said that banks were putting off decisions on where to focus their activity, and that this was dampening the ability of businesses to fund new projects.

Mr del Missier said uncertainty over the regulatory treatment of derivatives meant Barclays was more cautious on offering products used by corporations and their lenders to hedge currency and commodities price risk. “We don’t know how to think about the risk and whether to commit to those risks, and that affects the availability of credit,” he said.

The coming banking results season is expected to show the effects of a sharp downturn across Wall Street and the City of London.

Mr del Missier also attacked the US “Volcker rule”, due to be implemented in July, which bans banks from trading with their own money, except in US government debt. The exemption for Treasuries risks making other countries’ debt less attractive, and provoking tit-for-tat retaliation.