Two men were found guilty on Wednesday of plotting to murder and rob Grammy Award winning singer Joss Stone because they were angered by her links to the British royal family.

Junior Bradshaw, 32, and Kevin Liverpool, 35, planned to behead the singer before throwing her body in a river near her rural home in southwest England, prosecutors said.

The pair had a deep hatred for Stone because she had performed at a charity event organised by Princes William and Harry and she attended the wedding of William and the Duchess of Cambridge, formerly Kate Middleton.

Prosecutors said handwritten notes found at the men's flat described Britain's Queen Elizabeth and Stone as "devils" and talked of "destroying the queen's system".

Liverpool was jailed for life with a minimum term of 10 years and eight months after being convicted of conspiracy to murder and conspiracy to rob following a three-week trial at Exeter Crown Court.

Bradshaw will be sentenced later, the Press Association reported. Both men had denied the charges.

The prosecution alleged they planned to attack Stone at her home in Devon in June 2011. They were arrested nearby and police found a Samurai sword, three knives, two hammers, masks, gloves and a hosepipe in their car.

The prosecution claimed the pair had scouted Stone's home, although no direct forensic evidence was found to link the defendants to any of the weapons.

Presented by Adam Justice