Daniel Graham, 39, and Adam Carruthers, 32, have denied causing criminal damage after the 2023 felling of the tree at Sycamore Gap, which had stood for nearly 200 years in a dramatic dip in the landscape next to Hadrian's Wall, a UNESCO World Heritage site in northern England.

But prosecutors told Newcastle Crown Court the two men cut down the tree with a chainsaw "in an act of deliberate and mindless criminal damage," which they filmed on Graham's phone and then shared with others.

Prosecutor Richard Wright said the pair drove to the site near Hexham in Graham's Range Rover and felled the tree on September 27, 2023, slicing through the trunk in "a matter of minutes".

"Having completed their moronic mission, the pair got back into the Range Rover and travelled back towards Carlisle" where they lived, he said.

He said a video of the act recovered from Graham's phone was shared by the two men with "the unmistakable sound of a chainsaw, and a tree falling".

The next day, in a voice message from Graham to Carruthers, Graham said "it's gone viral. It is worldwide. It will be on ITV news tonight," Wright said.

"They are loving it, they're revelling in it. This is the reaction of the people that did it. They still think it's funny, or clever, or big," Wright said.

The pair are jointly charged with causing pound622,191 ($832, 821) of criminal damage to the tree and pound1,144 of damage to Hadrian's Wall, an ancient Roman fortification stretching from northwest to northeast England.

- Efforts to regrow tree -

When AFP journalists visited the site in the Northumberland National Park after the tree was felled, there were spray paint marks on the stump and it appeared to have been cleanly cut.

"These are men with knowledge of how to fell a tree of this size, had access to a wide variety of equipment and the relevant equipment, worked together to carry out tree felling and had a close friendship at the time," Wright said.

He also said the two shared jokes on social media about an "operation" they carried out on the night of the felling.

The felling triggered intense feelings in Britain and jurors were asked if they had any emotional connection to the much-loved site during the selection process on Monday.

The sycamore was a symbol of northeast England and a key attraction photographed by millions of visitors over the years. It was the Woodland Trust's Tree of the Year in 2016 and was used for a scene in the 1991 blockbuster film "Robin Hood: Prince of Thieves" starring Kevin Costner.

Efforts have been under way to see if the tree can be regrown from its stump or seeds.

The National Trust conservation body, which owns the wall and the tree, said it has grown 49 saplings from the sycamore's seeds, which will be planted this winter at sites across the UK.

The trial is set to last several days.