Military helicopters in the South West are in danger of being brought down by a threat they normally expect to face over Afghanistan.

Yobs aiming lasers are dazzling crews on night-flying training exercises. The Navy and police warn their action could bring death and disaster to local communities.

Earlier this month three Navy Lynx helicopters based at Royal Naval Air Station Yeovilton were targeted as they approached Merrifield airfield near Ilton. And on Wednesday night a spot light was shone at another Lynx as it flew over Ilton.

Previous incidents have involved Sea King Commando helicopters from the same base.

Crews wear night-flying goggles designed to intensify starlight and moonlight as they train for operations in Afghanistan. The light from lasers not only dazzles, but could damage their eyes, on-board equipment, and in some circumstances could cause a multi-million helicopter to crash.

Police helicopters, air ambulances and civilian passenger aircraft have been targeted across the West in the last year, with 90 incidents in the Avon & Somerset Police area alone in 2010.

Yeovilton’s ‘Commander Air’ Commander Neil Thompson warned that the actions are a criminal offence, and could bring disaster.

He said: “It would be considered a hostile act by an enemy. I am sure some people don’t realise just how dangerous their actions are and I want to highlight this. If a crew is so dazzled that they end up having an incident, or God forbid an accident, then not only their lives but those of people on the ground are at risk.

“We have had experience of this in the past but incidents are becoming more frequent. This is a crime under the UK Air Navigation Order, and is classified as a hostile act when it causes damage to the equipment and also to people.”

Detailing the incident which took place on January 3 Commander Thompson said: “Three Lynx were illuminated by a hand-held laser from the village of Ilton, by someone in a lay-by. They had to break off their approach because of the dazzle, then investigated where it came from and reported it to Avon & Somerset police who went to the scene, but whoever had done it had gone.”

Last year a Chard man was given a suspended prison sentence for aiming a laser at a police helicopter.

Police Constable Adrian Chilcott, based at Bristol Airport said: “Anyone who shines a laser at an aircraft performs a dangerous and reckless act. These people have no consideration for the safety of the aircraft or its crew.

“When this is targeted at a police helicopter it can put life at risk, hinder the apprehension of offenders and delay the investigation of crime. However, lasers are directed at all aircraft – including military, commercial and private planes.

“In 2010 there were 90 reported laser hits against aircraft and this is something we take seriously.

“The most recent laser seized was from children aged nine and 11 who had received the item as a gift, and this demonstrates a need for parents to educate their children about the dangers of lasers if they are misused.”