A false alarm about a sinking vessel in Pembrokeshire waters saw three emergency services take to the sea and air on Saturday.

Both of Tenby's RNLI lifeboats were requested to launch shortly before 11am following a mayday from a vessel taking on water three miles south of Caldey Island.

The lifeboats made best speed towards the casualty's last-known position.

Once on scene, they were joined by a police boat, Coastguard Rescue Helicopter 187 from St Athan and the passing cargo vessel, Arklow Valour.

Said Tenby RNLI spokesman Ben James: "After investigating several targets in the water, which all turned out to be driftwood, and with no vessels reported missing, all units were stood down at 1.25pm, with the call being classified as a false alarm."

The lifeboats returned to station, arriving at 1.35pm.

HM Coastguard Senior Maritime Operations Officer Daniel Young said:  "If we get an emergency transmission we always treat it as real.   

"If we think someone’s in danger or in trouble we will always search for them rather than risk loss of life.   

‘If this does turn out to be a hoax, we would take this opportunity to remind people that making deliberate, false or misleading calls is against the law and we treat it very seriously.

"We keep a record of these calls and hold those records as evidence for future prosecutions. Have no doubt, if you’ve been identified as making a hoax call, the MCA will seek to prosecute offenders to the fullest extent of the law.

"Not only do hoax calls waste the valuable time of our Coastguard officers, volunteers and resources such as the RNLI and our aircraft while searching; it also may be putting other lives at risk by diverting our resources away from genuine emergencies. 

"It also puts our emergency services’ crews lives at risk as they searched for nearly five hours with nothing found."