Alistair Keely The parents of two young children killed by carbon monoxide poisoning while on holiday in Corfu are backing a new poster campaign aimed at raising awareness.

Christi and Bobby Shepherd, aged seven and six, died in 2006 after carbon monoxide fumes from a suspected faulty boiler seeped into their holiday bungalow.

Their father, Neil Shepherd and his partner, Ruth Beatson, from Wakefield, Yorkshire, were also overcome by fumes but recovered in hospital.

The couple yesterday joined the victims' mother, Sharon Wood, and her husband, Paul, at the House of Lords for the launch of a school poster competition. Organised by charity CO-Gas Safety, it aims to raise awareness of the existence of carbon monoxide poisoning and other fuel dangers.

Since the tragedy, both parents have celebrated the birth of babies. The children's father, Neil, and his partner, Ruth, had a baby girl named Ruby Ella. Earlier this year their mother, Sharon, and her husband, Paul, had a baby boy, called Luke.

The families were in London yesterday to meet Ed Balls, Secretary of State for Children, Schools and Families, at the launch.

Paul and Sharon Wood said in a statement: "The last government awareness campaign was around 10 years ago.

"Lives are still being lost to carbon monoxide and we believe the majority of the population is still not fully aware of the causes or symptoms of CO poisoning.

"There is no doubt that education and awareness is the key to prevention. The most appropriate place to start is in schools. We urge government ministers and local authorities to support the poster competition."

Neil Shepherd added: "If my children were aware of the dangers and symptoms of carbon monoxide, they might have put the thought it could be CO into my head and just maybe they would be here today.

"I believe raising awareness through the poster campaign is a fantastic step in the right direction."

Colin Breed, MP and director of CO-Gas Safety, said: "I have watched the incredibly hard work done by this charity to try to persuade a wealthy industry to raise awareness.

"How can people protect themselves against a silent killer most people don't even know exists and cannot be sensed? I am deeply shocked that after over 13 years this tiny charity, run mainly by volunteers, is doing more to raise awareness than industry or government."