An 18th Century stately home has been left a "shell" after a devastating fire, the National Trust has said.
The blaze at Grade I listed Clandon Park House, near Guildford, led to widespread damage.
Roger Childs, from Surrey Fire and Rescue Service, said it began in the basement at 16:00 BST on Wednesday and spread quickly to the roof.
The fire was out by midday on Thursday but crews remained at the scene damping down. The blaze is being investigated.
The 1720s mansion was home to a prized collection of 18th Century furniture, porcelain and textiles.
About 80 firefighters tackled the blaze at its height and crews have managed to save a "significant" number of valuable antiques.
'Fears of further collapse'
Mr Childs said all valuable items were already tagged and identified and crews were working to retrieve them.
He said the intense fire burned through floors and ceilings and spread quickly through voids in the building.
BBC Surrey reporter Mirande Schunke said the smouldering building was surrounded by an "eery haze" and floors had been heard crashing down inside.
She said there was a lot of speculation about whether the building facade could remain standing now the floors had caved in.
She tweeted: "Safety cordon being extended as cracks spotted in lintels at this corner of @ClandonParkNT".
June Davey, one of the 170 volunteers who work at Clandon Park, was on duty at the mansion before the fire broke out.
She said: "We had the most beautiful morning, lovely volunteers. It was heavenly. I stood in the room and thought how lucky I am just to be in the house."
Mrs Davey, who was recognised in the New Year's Honours for her volunteer work, said: "We found out very quickly they had got everybody out. We have got a very clear evacuation procedure."
She said two members of staff lived in the mansion and had lost their homes and belongings.
"It's like a big family," she added. "It's like your own house. We are absolutely shattered. We feel as if the ground has caved in."
Dame Helen Ghosh, director general of the National Trust, said the interior of the stately home was essentially "a shell" after most of the roof, lintel, ceiling and floors collapsed.
She said it was heartbreaking to witness the damage and the fire had come as a terrible shock and a devastating personal blow to staff and volunteers.
"We have saved some significant items but certainly not everything that we wanted to save," she added.
Visitors have been urged not to visit the scene.
Geri Silverstone, National Trust spokesman, said staff still had no access to the building.
He said staff at the property had practised fire drills on a regular basis.
Clandon Park was built by a Venetian architect for Lord Onslow and the estate was passed down through generations of the family.
The building, which has become a popular wedding venue, was left to the National Trust in 1956.
A member of the family, Dr Arabella Onslow, whose father was born in and grew up in the house, said she was "shell-shocked".
She said she saw pictures of the fire in the roof and also heard it was thought to have started in the basement and realised "literally the whole place was ablaze".
The Cumbria GP said she knew she was in an unusual and privileged position to have an ancestral home but added: "Equally it's my family and it is quite devastating."
Some couples who were due get married there now need other venues.
Peter Page tweeted: "So sad about Clandon Park. Due to get married here on 30 May. Can any wedding venues in Surrey let me know if they have any availability?"
And Mark Nickols tweeted: "@OC my brother was supposed to be getting married at Clandon House on Friday. We now have 24 hours to plan a wedding.."