Ryanair shares tumbled 23 per cent yesterday after surging fuel costs and falling fares forced the airline to report a heavy first-quarter loss and warn it could fall into the red for the full year for the first time since it floated 11 years ago.

Ryanair, Europe's biggest low- cost carrier, reported an 85 per cent fall in underlying net profits for its first quarter from April to June from €139m (£110m) to €21m, and said it could fall to a loss of up to €60m in the full year to March 2009.