BOAT owners have been warned to guard against carbon monoxide poisoning by safety investigators after a couple and their pet dog were killed during a summer holiday in Norfolk.

Carpenter Alan Frost, 64, and housewife Tina Leticia Wilkins, 51, from Essex, were found dead on June 9 after a member of the public became concerned that their motor cruiser, 'Love for Lydia', had been moored in the same place on the River Bure for some time.

An inquest heard they had succumbed to carbon monoxide poisoning.

The latest tragedy comes after the deaths of two fishermen who were poisoned while they slept on a vessel moored in Whitby in 2014, and the case of a mother and daughter killed by a lethal leak of carbon monoxide from a faulty portable generator on board their motor cruiser on Lake Windermere in 2013.

The Marine Accident Investigation Branch (MAIB) is today urging boar owners to be as vigilant to the potential danger from carbon monoxide as they would be at home or in a caravan.

MAIB Chief Inspector Steve Clinch said: “Carbon monoxide alarms are commonplace in our homes and in caravans, but the tragic deaths of a couple and their dog on Love for Lydia are a reminder of the dangers of carbon monoxide on boats.

“This is the third double fatality due to carbon monoxide poisoning that we have investigated in around three years.

“There are many sources of carbon monoxide on boats including engines, generators, solid fuel burners and cookers. Canopies on deck can allow poisonous gases to build up, quickly reaching fatal levels. Ventilation is essential."

Symptoms of carbon monoxide poisoning include headaches, dizziness, nausea, vomiting, tiredness, confusion, stomach pain and shortness of breath.

The MAIB inquiry into the 'Love for Lydia' tragedy is ongoing but investigators believe exhaust fumes from an inboard engine which had been left running "probably to charge the batteries" were blown under the canopy and towards the accommodation area.

Tests have suggested that the carbon monoxide may have reach high levels inside the accommodation area in just three minutes.

It was not ventilated and no carbon monoxide alarms were fitted.