ICAP blamed the eurozone crisis and “constraints on market liquidity” for weak trading volumes in derivatives in the year to March, which caused the interdealer broker’s revenues to fall 3 per cent.

Michael Spencer, Icap’s chief executive, said that the company had prepared its trading systems for a Greek return to the drachma. “Bluntly, they just need to organise it as efficiently as possible,” he said.

ICAP suffered a 7 per cent fall in pre-tax profit, with particularly weak trading volumes in US corporate bonds, while operating profit from voice broking in the Americas fell by more than a third.

Operating losses in Icap’s Brazilian operation widened from £10m to £12m, largely because of restructuring costs. However, the company expected to break even in Brazil within a year. The shares rose 0.1p to 335.4p.