Managing director Leo Tommony, 54, watched in horror as the reception area of Lancashire Granite's building in Titan Way on the Moss Side Industrial Estate, Leyland, burst into flames.

He had been bundled into the building by his attackers as he locked up on Saturday before being tied to a fence outside the premises.

He could then only look on helplessly as his premises went up in smoke.

The raiders, who were all wearing balaclavas, had forced Mr Tommony to disabled the alarms in the building before marching him to the back of the building and tying him up.

The police have so far not said whether anything was stolen during the raid. Insp Graham Smith, of Lancashire Police, told of how the boss was forced to watch as the building was "engulfed in flames".

He said: "Police are appealing for anyone who saw any persons or vehicles acting suspiciously in the Moss Side Industrial Estate area between 4.30pm and 5pm on Saturday."

Lancashire Granite, which has operated from its base in Leyland for 25 years, sells bespoke granite materials which are used in high-quality kitchen units.

Det Sgt John Cass, of South Ribble CID, said: "It is unclear what the motive was at this stage of our investigation, and we are looking at whether anything was taken during the incident."

Anyone with any information is asked to call Leyland Police on 01772 415917 or Crimestoppers anonymously on 0800 555111.