Thinking nothing of his own safety, PC Dell rescued Christine's son from their blazing flat, then returned to pull her husband's unconscious body from the building just moments before the floor collapsed in flames.
What makes PC Dell's story all the more remarkable is that he has had a fear of fire ever since he saw three teenagers burn to death in a car accident 21 years ago.
His phobia is so bad that he can't even watch his own children light the candles on their birthday cakes.
PC Dell, 43, says: "When I discovered there was a fire down the road I told my colleague to call the fire brigade, ran out and saw the road was full of smoke. A woman from the flat was cradling her daughter in her arms and was quite hysterical."
He learned that Christine's 10-year-old son, David, was trapped on the second floor. He says: "The building was full of smoke and over the roar of fire I could hear him screaming above me.
"When I reached the second floor the screaming had stopped and I just felt around and found him upstairs."
Using his body as a shield to protect the semi-conscious child, PC Dell somehow found his way out of the building.
But as he placed David into his mother's arms, she told him that her husband was also inside - on the third floor directly above the seat of the fire.
Followed by PC Jim Pollock, who had joined him from the station, PC Dell, of Tavistock, Devon, re-entered and crawled back upstairs.
PC Dell says: "It was like putting your head in an oven, the heat was absolutely unbearable. We eventually found his body collapsed beside the bed."
The fire, which happened in Cannington in February of last year, left PC Dell, of Devon and Cornwall Constabulary, needing hospital treatment for burns to his hands, neck and face. The smoke he inhaled means he will have asthma for life.
He says: "Having been through a few fires in the past, I find these situations particularly difficult to deal with."
His phobia started in 1981 when he was called to a road accident and watched, powerless, as three teenagers burned to death inside a car.
In 1987 he saved eight people from a burning building and 10 years later pulled a man from a wrecked car. PC Dell says: "His girlfriend was trapped and I had to give her artificial respiration. Petrol was leaking and I was just hoping it didn't explode.
I have an abnormal fear of fire. When it is my childrens' birthdays I can't even bear to see their faces illuminated by the candles on their birthday cakes."
Christine, 37, said: "I owe him a lot of gratitude - he is a policeman in a million."