A call for help that prompted a major search involving dozens of rescuers may have been a hoax.

Three RNLI lifeboats and a coastguard helicopter were scrambled after the alarm was raised on Saturday afternoon.

The radio broadcast, which was made on a channel reserved for emergency calls, claimed a kayaker was in distress near Banff, Aberdeenshire.

Rescuers carried out an extensive search on Saturday followed by a scaled-back operation on Sunday but found no evidence of anyone in danger.

The Maritime and Coastguard Agency has now called off the search and says the alert was probably a false alarm.

It believes the broadcast was not sent while at sea and said it has found no evidence of kayakers in the area on Saturday.

HM coastguard duty controller Matt West said: "The voice recording has been subject to multiple playbacks and the absence of background noise has cast doubts that this transmission was made at sea in rough conditions."

He said the rescue operation had put the lives of those involved in danger and warned hoaxers would be prosecuted.

"On Saturday, the weather conditions were extremely rough with the seas four to five metres high," Mr West added.

"Our crews searched into Saturday evening and again the following morning with nothing found.

"There are no plans to resume this search unless further information comes forward."