After confirming the tumble drier wasn't on fire, I set off with the dog in search of the source of the smoke that was drifting round Briarwood. I eventually found it coming from some trees in a garden so I peered over the fence but couldn't see anyone around so I went and knocked on the kitchen window with my best ex-door to door salesman knock (ie. loud) but got no reply so I phoned the fire brigade.
A fire engine arrived after about 10 minutes and firemen started climbing up the fence. It turns out that someone was in the house after all - they didn't answer when I knocked but they did when a fire engine parked on their drive and firemen started climbing up their fence. The occupant had been burning rubbish in a bin in their garden and left it unattended so no emergency this time but it's best to be safe than sorry, especially after the recent spate of fires in Brookside.