The offender called the fire and rescue service at 2pm on Wednesday afternoon, and falsely reported that a teenage boy had fallen into the water near the Celtic Gateway, Holyhead.

In response, a multi agency rescue team was scrambled to the scene, including 22 Squadron from RAF Valley, the North Wales Police helicopter, the Holyhead RNLI inshore lifeboat and firecrews from Holyhead and Bangor.

Holyhead RNLI spokesman Ray Steadman explained that the launch of the RNLI lifeboat alone cost £3,000; he said: "It was a big operation, and a big consequence of this was that it directed the emergency services away from potential other incidents.

"We would deplore anyone who would pull this sort of stunt, and in the recent past the powers that be have brought in quite a number of hoaxers to justice."

The search was stopped shortly after 3pm, with all agencies involved agreeing that there was no evidence of the reported incident taking place.

A spokeswoman from North Wales Police added: "We take any incident of this type very seriously, and an investigation is underway.

"Anyone with any information can contact us on 0845 607 1002 (Welsh line) or 0845 607 1002 (English line)."