The famous tree at Sycamore Gap, next to Hadrian’s Wall, was made famous by actor Kevin Costner when it appeared in his 1991 film Robin Hood: Prince Of Thieves.
Northumbria Police said they were investigating whether a criminal offence had been committed after pictures emerged on Thursday morning of the tree lying on its side by the wall, after apparently having been cut down.
On Thursday morning the national park authority said: “(We) can confirm that sadly, the famous tree at Sycamore Gap has come down over night. We have reason to believe it has been deliberately felled.
“We are working with the relevant agencies and partners with an interest in this iconic North East landmark and will issue more details once they are known.”
The authority is asking the public not to visit the site, near Crag Lough, “whilst we work with our partners to identify what has happened and to make the site safe”.
A spokesperson added: “Sycamore Gap was voted English Tree of the Year in 2016 in the Woodland Trust’s awards and is much-loved by people from across the world.”
The Sycamore Gap tree is probably the most photographed in the country and stands in a dramatic dip in Hadrian’s Wall.
The Northumberland National Park Authority’s website says the Roman Milecastle 39 is just to its left.
Sycamore Gap is looked after by both Northumberland National Park and the National Trust.
The news was met with dismay and outrage by walkers’ groups on social media.
A Northumbria Police spokesperson said: “We can confirm an investigation has been launched following damage to the Sycamore Gap Tree in Northumberland.
“Enquiries are ongoing to establish whether any criminal offences have been committed.”