A man was jailed for life on Wednesday for plotting to rob and kill British pop star Joss Stone with an accomplice and dump her body in a river.

Kevin Liverpool, 35, and his co-accused Junior Bradshaw, 32 -- who will be sentenced at a later date -- were arrested in June 2011 a few miles (kilometres) from Stone's rural home in the county of Devon, southwest England.

An array of weapons -- including a samurai sword, hammers and a metal spike -- were found in their battered car after they were arrested.

Residents near Stone's home had alerted police after the pair stopped to ask directions.

Liverpool was told by a judge at Exeter Crown Court in Devon that he would have to serve at least 10 years and eight months in prison before he could be considered for parole.

The two men were convicted by a jury of conspiracy to murder and conspiracy to rob after just four hours of deliberations following a three-week trial.

Judge Francis Gilbert told Liverpool: "It was your scheme.

"This may have been the crazy scheme of a crazy person... but it was a very real plan.

"You intended to rob her and kill her and dump her body in the river, according to your words, and then leave the country with your accomplice Junior Bradshaw."

Notes found in the defendants' possession showed they intended to decapitate the pop star before dumping her body in a river, the jury was told.

Stone, 25, was at home at the time but she said in evidence during the trial that she was only aware of the incident when police contacted her later that day.

She described the house, accessed by narrow country lanes, as an "open house" for family, friends and her then boyfriend.

The star admitted that before the plot she had lax security and rarely locked her front door, adding: "But I do now."

The hapless pair of would-be attackers encountered a range of problems during the 240-mile (390-kilometre) journey from their home in Manchester, northwest England, to the village where Stone lived.

They were stopped by police after being involved in a crash on the way, but were allowed to continue their journey in their damaged car.

The jury heard Bradshaw and Liverpool also asked a postman for directions to Stone's home by showing him a photograph of the singer, who burst onto the international music scene in 2003 with her platinum-selling debut album "The Soul Sessions".

The men were eventually arrested after they stopped again to ask local residents how to find Stone's home.