The announcement is likely to set the Trust at odds with the Onslow family, who have owned the house since it was built to when it was handed to the Trust in 1956, who have said they do not wish it to be rebuilt.

The 8th Earl of Onslow, Rupert Onslow, a hereditary peer and insurance broker, has said he would prefer the money to be spent on preserving other Trust properties for the nation, saying Clandon as he knew it is “lost”.

The Trust has now said it is confident that “a number of principal rooms on the ground floor could and should be restored given their architectural and historical significance”.

It insisted it was not intending to “recreate the rooms as they were the day before the fire”, but return to the original 18th century plans and work from there.

Fire ravages the 18th Century Clandon Park near Guildford, Surrey  Photo: PAUL BURGMAN

It will now consult with architects and conservation bodies to determine how to “bring the space alive in a bold and imaginative way”.

The upper floors, considered to be less architecturally significant, will be turned into spaces for exhibitions, events and performances.

Members of the public will eventually be consulted on a shortlist of ideas for the property.

The Trust said it had spent nine months reviewing a “number of options” for the property, and had concluded restoration was the best idea.

It will be funded largely through the insurance payout from the fire, with the Trust planning to fundraise towards the end of the project to make up the costs.

A picture frame is removed from Clandon Park following the fire  Photo: National Trust

The 8th Earl of Onslow has previously said he does not wish the property to be rebuilt.

Instead, he told a newspaper, he would prefer for the insurance payout, which he estimates will be about £65 million, to be spent on another National Trust property.

“Clandon is lost,” he said last year. “It’s a ruin now. It decayed instantly. This sad site should be left in peace and tranquillity.

“The last thing we want now is a replica. If the National Trust wants a replica, let them build it somewhere else.

“I feel the nation and the members would benefit more from a Grade 1 listed house that is in need of its own land, with a farmyard and stables, rather than by spending the insurance money on the largest, most vulgar mock-Georgian footballer’s wives house.”

Fire crews tackle the flames at Clandon Park

The Trust said the insurance policy would not allow the money to be spent on another property, and must be invested at Clandon.

Dame Helen Ghosh, the Trust’s director general, said: “Today marks an exciting new chapter in the Clandon story, and will represent one of most ambitious projects ever undertaken by the National Trust.

“The fire at Clandon was shocking, but gives us the opportunity not only to show our respect for the heritage of the past, but also to create new heritage for the future.