A fault in the radar system at Dublin Airport has caused significant disruption to flights and has delayed thousands of passengers.

The Irish Aviation Authority said the airport was operating at only half capacity this evening. Earlier, all flights into and out of the airport were grounded for a time, for safety reasons.

Aer Lingus said it had cancelled 23 flights. Engineers from the French firm which built the radar system and a sub-contractor are trying to rectify the problem.

Ryanair said it had been forced to cancel almost all flights to and from Dublin Airport from mid-afternoon onwards, involving a total of 74 flights. It has called for a Government investigation into the situation.