Three fire engines were called to Laburnum Grove at 5.29am by a neighbour who said there could be people inside the house.

Firefighters broke into the terraced house and found the ground floor well alight but a search of the property established that there was nobody inside.

They also had to break into the house next door, which was heavily smoke-logged, but that too was empty.

Crews tackled the fire wearing breathing apparatus and using two hose reels and two jets. The smoke alarm was melted by the fire.

Watch manager Leo Loughrey, of Lancaster Fire Station, said: "Crews were faced with a very serious fire involving the whole of the ground fllor with flames coming out of both the front and back windows.

"The police told us the man who lived at the house had not been there for a week or two and the man who lived at the next door house was staying at his girlfriend's.

"It is definitely lucky there was nobody in either house at the time."

Police and fire investigators say they are treating the fire as suspicious.