Flames roared through the Grade II listed mansion in Moreton Morrell, owned by Warwickshire College, last Thursday night.

Some 80 firefighters from across the Midlands used 15 engines and hydraulic platforms to tackle the blaze, which broke out at about 3.45pm.

Such was its intensity the last embers were not extinguished until Saturday, by which time the building "was just gone", said college principal Ioan Morgan.

On Wednesday he revealed investigators have now deemed the incident an accident.

The hall was part of the college's Moreton Morrell Centre agricultural school but was used primarily for conferences and weddings. It is believed to have burned after flames took hold in the roof.

The principal told how 12 equine studies students with rooms in the building had left for their Easter break just 24 hours before.

He said there was no suggestion of any student involvement, adding: "Firstly we are relieved there were no injuries or loss of life. Had this happened a day earlier it could have been a very different story.

"So we have lost a building - and a special one. It was our oldest and the place where the agricultural wing of the college started with just 20 students. It is a complete loss and looking at the aerial photos it reminds me of a decayed tooth.

"But it is insured. We will rebuild it and to the requirements of its Grade II listing, which means much of the outside will look the same and some key features inside, although we may in fact to be able to make it more fit for purpose.

"We would hope the work would be complete by 2010."

The disaster came just two weeks after it was announced the Georgian-style mansion, built in the early 1900s, had been shortlisted as a venue for training camps ahead of the London 2012 Olympic Games.

It will appear in the official list of suitable venues distributed to teams from around the world.

"We should be ready in plenty of time," added Mr Morgan, who thanked the insurance teams at the National Farmers' Union.

Surveyors and structural engineers were busy making sure the remaining structure was safe this week.

Fire crews from Oxfordshire, Hereford, Worcestershire and the West Midlands all rushed to the scene last Thursday to find ground, first and second floors and the roof all well alight.

Ambulance officer Nigel Wells watched the drama unfold. He said: "The site was a beautiful manor house.

It was also used as a conference centre and for weddings and was a historical landmark. It is a real shame and very sad to see it all go up in flames."

The hall is part of the Moreton Morrell Centre, where Warwickshire College runs its agricultural and construction courses.

The site includes halls for 300 students, stabling for 100 horses, an equine demonstration area and a 345-hectare commercial farm.