It was recently confirmed that a fire that destroyed an 18th Century mansion started accidentally and was probably caused by an electrical fault, investigators have said.

Clandon Park House near Guildford, was reduced to a charred shell during the blaze.

The mansion housed a large of collection of furniture, porcelain and textiles including at least six Victoria Crosses and one of the footballs kicked across no-man’s land on the first day of the Battle of the Somme in 1916, all of which perished in the fire. Although some of the paintings and furniture from the house were rescued many tapestries and some porcelain were also damaged.

It was most likely the result of a faulty connection in the electrical distribution board according to a fire report

A full review of fire prevention policies has begun for all National Trust locations.

A lack of fire protection to the fuse cupboard ceiling and the stately home’s historic design allowed the fire to spread, the Surrey Fire and Rescue Service report said.

Such buildings are adapted over the years to add amenities, producing hidden voids that may or may not be known because of the loss of buildings plans and records, it added.

‘Checks on all mansions’

“It is the hidden voids in this type of building that allow unpredictable and uncontrollable fire to spread,” it said.

Assistant chief fire officer Simon Moore said the National Trust had been advised of the findings.

Staff evacuated the house safely and no-one was injured. A salvage plan helped to save contents and fire detection systems operated as they should have done, she said. Mr Moore said the fire service had begun work with the trust to consider what more could be done to improve the fire safety of their other buildings.

The trust said none of its staff would have been able to identify the fault as a potential issue, and unfortunately it had not been detected during professional checks by electricians.

In spite of this it still highlights the importance of periodic electrical testing in order to minimize potential risks wherever possible.

Fire broke out at the Grade-I listed building in April, reducing it to a shell.

One room – the Speakers’ Parlour – survived and hundreds of items have been rescued.

Make sure that your electrical system is fully tested and safe