Young Joshua Parker alerted his mum Tara Newman after he spotted a heater in his bedroom burst into flames, and she woke four-month-old baby Joey and took him out of the house.
Joshua rescued his pet hamster Mr Fuzzy before closing the bedroom door while his mum called firefighters, who raced to the flat in Turing Drive, Easthampstead.
Joshua told the News: “It was pretty amazing.
“I had a light on and was reading a book.
“I heard a pop and sizzle and saw flames coming out of the heater.
“I ran out of the room and told my mum. I think if I hadn’t seen it it could have risked our lives and other people’s because we are in flats.
“I felt very proud of what I did,” he said.
Joshua revealed he was reading Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers when he saw the heater ignite.
He said: “It was very scary and I was happy everyone was safe.
“I forgot about the hamster but went back and got him.
“There was a lot of smoke in the room and it was black.”
After rescuing Mr Fuzzy, Joshua then left his bedroom and closed the door behind him to contain the fire. Two fire crews, from Bracknell and Wokingham, arrived at the scene at about 6.30pm on Monday last week to find the family and some of their neighbours outside the building.
The firemen entered the building and found the heater smouldering with the room filled with smoke.
They spent about 30 minutes making sure the fire was out and ventilated the room.
Tara joked that Joshua should have been asleep after she read him a bed-time story – but added she believed that by staying awake he saved their lives.
She said: “If he’d gone to sleep with all that smoke in there he could have died. I’m incredibly proud of him.”
Tara added that Mr Fuzzy was important to Joshua because she had given the pet to him as a present for good behaviour.