A woman aged 90 tackled a fire out-side her home on her own - but her neighbours were not so lucky.
Now police are probing the mystery blazes which started in rubbish bags left outside back doors and ended in the partial destruction of a flat.
Florence Oliver, 90, of Barra Hall Road, Hayes, managed to extinguish the fire outside her home herself, after her pet dog, Boots, woke her up at about 2.30am on Sunday.
She said: "My dog started barking and it kept running to the back door.
"I thought it wanted to go out but when I opened the door the fire just burst in, so I got bowls of water and threw it over and managed to put it out.
"When the firemen came round they asked me who put the fire out?
"And they looked surprised when I said I did. But it was my dog that saved me.
"It's obviously arson and what these people have done is really senseless.
"What are they getting out of putting people through so much upset?"
Now she doesn't feel safe when she goes to bed and is unable to sleep at night.
David Rodgers, 62, of Sycamore Avenue, said: "We were asleep and my friend heard an explosion in the flat and woke me up.
"We went to the back door and we saw flames coming into the kitchen. I was trying to find something to put it out with but the next time I looked the flames just blew up to the ceiling so we both ran out."
He said he then went upstairs and started banging on his neighbours' doors to get them out and the fire brigade arrived shortly afterwards. The kitchen of his flat is severely damaged.
Mr Rodgers said: "I think whoever did this is just sick, I just pity them, they have no intelligence, they probably thought it was a joke but they could have killed someone.
"If it was an elderly person they could have died."
Police have declined to comment. Two properties, in Sycamore Avenue and Barra Hall Road, and one in nearby Juniper Way were affected. Some 20 people were temporarily evacuated from their homes.