Ten distress signals, set off on Saturday, were spotted by boats and people on the County Antrim shoreline.

Steve Palmer from the coastguard said spent cartridges were later found on a fishing boat in the harbour.

He said time and money had been been wasted. "It is illegal to let a flare off unless you really are in distress."

Mr Palmer said people seeing the flares, which are an international distress signal, would think somebody was in trouble and notify the coastguard.

"We then go into action by alerting lifeboats, if required, and a helicopter and also our coastguard rescue teams.