A disgruntled fast food worker burnt down the Burger King restaurant he worked in while customers were eating inside, a jury has decided.
James started the fire after an argument with his manager
Aaron James, 20, set nine separate fires in the burger bar in Poole, Dorset, after an argument with bosses.
Bournemouth Crown Court heard James had "an unhealthy fascination with fire".
The judge told him he faced a long jail sentence after he was found guilty of arson while being reckless as to whether life was endangered.
He said he was concerned for James' mental state and would await psychiatric reports before sentencing him.
James started the fires on 16 October, 2003, after his work had been criticised by his line manager.
He piled up burger wrappers and set fire to them in the kitchen, eating area and the manager's office.
Around 15 customers had to flee the building as the fire took hold.
He got the idea after youths set light to a wheelie bin outside the restaurant, the court heard.
James was remanded in custody until 1 October, when he will be sentenced at Bournemouth Crown Court.
Det Con Paul Harburn of Dorset Police said after the hearing: "I'm satisfied with the result.
"It was a very serious fire and it was only down to the quick thinking of members of staff that there weren't any serious injuries or loss of life."