THE cause of the blaze that wreaked havoc at historic Allerton Castle may not be known until the end of this month at the earliest, it was confirmed today.

Firefighters have been unable to probe the badly damaged seat of the blaze, which happened nearly two months ago and that destroyed a third of the historic stately home causing millions of pounds of damage.

Officials had initially estimated a cause could be known by mid February.

But North Yorkshire Fire & Rescue Service group manager Trevor Lund told the Evening Press that plans to construct a 80ft crane big enough to allow crews to examine the chimney where the January inferno is believed to have started have been hit by problems.

He said: "We can't get to the seat of the fire safely until the crane has been put in place. Access is very awkward.

"Until we are able to get closer to the chimney in a wing of the extension any conclusions on what caused the fire are speculation."

Once the giant crane was built, he said, fibre-optic equipment would be used to look for possible safety defects.

He said one crane had been put up at the site, but that did not have the required reach. Fire brigade equipment is about ten metres too short for the job, he added.

But Mr Lund said a road has been laid behind the castle allowing access for HGVs during the rebuild operation. This will give the emergency services speedier access in the event of another blaze.

Pressed on when a report outlining the cause of the fire would be finished, the group manager said: "I would hope that we are in a position to make conclusive statements by the end of March - but it could be longer."

He said further delays would not help the investigation, as evidence would be deteriorating.

He confirmed that an interim report, outlining the timetable events leading up to the fire, had been sent to fire chiefs.

The inferno left most of the roof and the historic dining room at the Knaresborough stately homes gutted. But most other rooms - including a substantial section of the Great Hall - survived.

More than 100 firefighters tackled the blaze at its height.

Officials have confirmed that 84 weddings were booked at the popular venue so far this year.

A large marquee for receptions is in the grounds while safety work continues on rooms usually used for weddings, and the first civil ceremony since the fire took place last week.

Castle officials have confirmed that approval was granted on March 12 for wedding receptions to take place inside the castle, but the library, dining room and state bedroom will not be available yet.

Updated: 08:52 Monday, March 21, 2005