The duo, PC Shand Panesar and PC Craig Nicholson, exclusively told Hillingdon is Here how they entered the blazing property in Bridgwater Road, South Ruislip, despite being unable to see, due to the billowing smoke.
Having arrived on scene before the fire crews, the policemen heard screams begging for help.
PC Nicholson shouted back to the man, to ascertain where the voice was coming from, before dashing in.
He said: “I couldn't see. From the front door you couldn't see the top of the stairs. I held my hands out but I couldn't see my hands, I had to feel where the people were at the top of the stairs.”
He bumped into the man, who had entered the home trying to help before they arrived, and then found a woman passed out on the floor. He grabbed her and dragged out of the house onto the drive way.
The officers are pictured above
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Meanwhile, PC Panesar prepared first aid by the front door, and came into the bottom part of the house, as his colleague rushed her out.
Her predicament, at that stage, looked grave.
PC Nicholson said: “She was completely unresponsive, there were no signs of life, she was not breathing. I was genuinely concerned that we were too late.”
He started CPR there and then, with neighbours milling around and watching, while the man, who had escaped with them, was clearly 'distraught'.
As this was happening, fire crews from three stations arrived and began battling the blaze, with flames being seen out of the back of the building.
The police officers continued to treat her on the drive, as the fire crews rushed to extinguish the blaze.
Eventually, the lady showed some signs of life, when the officers saw her stomach move slightly, indicating she had begun to breathe on her own. The pair could then see she had a pulse.
PC Nicholson, who performed CPR for the first time in his career, said they were 'amazed' at seeing the first indications of life and were deeply relieved.
PC Panesar explained that, had they arrived even just a little later, both people inside the house would have probably perished.
He said: “If it had been a few minutes later or the other gentleman in the house (who shouted for help and alerted them where they were) had been passed out as well, we wouldn't have got them out of there.”
Asked how it felt to know they had saved someone's life, he said: “It is difficult to describe. You've made the ultimate difference to somebody, in other words they're not dead, they're still alive because of what you managed to do.
“I'm not going go down the route of the cliché saying it's a warm feeling inside, but every so often I get a little something at the back of my head saying 'somebody is alive because of you' and it brings a smile to my face. I suppose it's indescribable really.”
PC Nicholson said he felt compelled to act, despite the obvious dangers and not having been trained in dealing with fires.
He said: “When you hear someone calling for help it is just kind of ingrained in you to go and help them, especially knowing someone is in imminent danger.
“Luckily we managed to do it and we were successful, which was great.”
An ambulance arrived to assist them and the woman woke up in hospital an hour later. Detectives have told the duo, who haven't had a chance to meet her yet, that she's recovering and is going to be okay.
The severity of the blaze was shown by the fact it took 21 firefighters nearly and hour and a half to extinguish the blaze after they arrived about 8.40pm. The cause of the fire, which started in the kitchen, is under investigation.
The duo have been praised for their 'exceptional act of bravery' by Metropolitan Police Service chiefs.
They were quick to point out, however, that the rescue operation had been a team effort with key assistance from the call operators in particular.
When the centre received a phone call from the woman all they could hear was a fire alarm going and a dog barking. She said there was a fire and she was trapped but then she then went silent and appears to have passed out. The operators had to try to work out where she was calling from.
The police duo, part of the Hillingdon Emergency Response Team, happened to be close by when the phone call came through.
PC Panesar said: “It was down to teamwork that it wasn't any more serious than it was and ended in a great result.”
They paid tribute to the other emergency services teams and especially the call centre staff for working out the location of the victim's house.
They said one female firefighter, in particular, had provided “amazing support”.
Acting Chief Superintendent Colin Wingrove of Hillingdon said: "This represents an exceptional act of bravery by the police officers who put themselves in harm's way to enter a burning building and save a woman's life. I am extremely proud of the officers."
Fire crews from Ruislip, Northolt and Southall stations all helped tackle the blaze.