“I was woken up by somebody hammering on the door,” said Mrs Wilma Mitchell of Broughty Ferry Road.

“He just told me to get out and if there was anybody else in the house to get them out as well.

“My son was behind me so both of us got out and waited for the fire brigade.

“I’ve no idea who he was. I just know that he was a Travel Dundee bus driver.

“I’m glad he did come to the door. The smoke alarm went off after we got outside, so we’d have got up, but it was very brave of him.

“I’d like to say a big thank you to him.”

The outbreak, which is being treated as suspicious, occurred around 4.40am.

Mrs Mitchell had fallen asleep in her living room, but was awoken by a phone call from a friend around 12.45am.

After putting the phone down, she closed the living room door behind her.

Hours later, the fire broke out in a bin recess outside and spread inside, burning the patio door and leaving the living room logged with thick black smoke.

It appears a wheelie bin and Mrs Mitchell’s grandchildren’s toys — which were directly outside the living room doors to the patio — caught fire and flames reached as high as the first-floor window.

“I usually sleep in the living room,” Mrs Mitchell said.

“I got woken by a phone call at quarter to one, otherwise I would have been in the living room.

“If I’d still been in the living room I wouldn’t like to think what might have happened.

“It all happened so quickly that I didn’t have time to be frightened.”

Neighbour Sandra Wright praised the bus driver’s quick actions.

“He was going past in his car on his way to work and stopped in the middle of the road. He ran and banged on the door and got them out,” she said.

Firefighters extinguished the blaze using a single hose reel.

A police spokesman said, “The incident is being treated as suspicious. CID officers are carrying out investigations at the scene.”

Scenes of crime officers were this morning analysing the seat of the blaze.