Firefighters are mystified over the cause of a blaze which filled a block of flats with smoke yesterday.

Occupants of a first-floor flat in Woodfield Road, Bicester, were set to jump from a window after fire broke out in a ground floor hallway.

All five residents escaped safely, after police, who were first at the scene of yesterday morning's fire, opened doors, clearing smoke from the semi-detached building

One resident was treated for minor smoke inhalation.

Peter Morgan, 50, who lives in a ground floor flat, was woken by a neighbour, John Philip, 53, who raised the alarm.

He said: "John woke me up and said there was a fire. Then he dragged me outside by my collar."

The fire is thought to have started among a stack of paper kept in the hallway, but firefighters are unsure whether it was started deliberately.

Although the property had smoke detectors, no batteries were fitted.