Detectives are investigating after a man accidentally set himself on fire in an arson attack on a working men's club in the early hours of today.

An off-duty policeman spotted the arsonist, who is believed to be in his 20s, smashing a ground-floor window of Hightown Liberal Club in Halifax Road, Liversedge, and pouring petrol into the building, West Yorkshire Fire Service said.

The firebug ran away whan he saw he was being watched but his clothing had caught light.

Police are now hunting the man.

The attack, which "gutted" the ground floor of the building happened at 1.05am today.

About 20 firefighters from Cleckheaton, Brighouse, Batley and Dewsbury spent about three hours tackling the blaze.They used breathing apparatus to check nobody was trapped inside the burning building but found it to be empty.

A fire investigation team and police scenes of crimes officers were at the scene and are expected to return later in the day.

Chris Atkinson, crew manager at Cleckheaton, said: "An off-duty police officer was coming home, heard breaking glass and saw someone trying to burn it down.

"It started on the ground floor. he broke the window and poured petrol through. He stepped back and set fire to a rag and set himself on fire. He was dancing round on the bowling green when the off-duty policemen tried to apprehend him.

"He may well have superficial burns."