A man who attempted to steal a "priceless" version of the Magna Carta was tackled by tourists as he tried to flee the scene.

Mark Royden, who lives in Canterbury, used a hammer to smash his way into a security case holding the historic document at Salisbury Cathedral.

Footage of the crime released by police

The 47-year-old was today convicted of attempted theft and causing almost £15,000 worth of criminal damage to a display unit during the raid.

A jury at Salisbury Crown Court heard Royden scoped the cathedral for a route avoiding CCTV cameras and went equipped with a hammer, gloves and safety goggles.

Before smashing the security case holding the artefact, he twisted a CCTV camera in another direction in a failed bid to avoid being recorded and then set off a fire alarm as a distraction, the court heard.

After failing to reach the historic charter, he ran from the scene but was chased by members of the public, including a pair of American tourists, cathedral staff, and stone masons.

They detained him in a works yard outside until police arrived.

Royden told police he thought the artefact may have been a fake, but Judge Richard Parkes QC told the jury its authenticity was not in question.

He asked for a pre-sentence report to be prepared on the defendant, saying he was almost certainly facing jail time.

He remanded Royden in custody until sentencing on February 25.

Det Con Richard Barratt, from Salisbury CID, said: "This is a case which has understandably attracted significant attention due to the priceless and irreplaceable nature of the document in question.

"We may never understand Royden's motivation in carrying out this attack, but luckily no lasting damage was caused."

The Very Reverend Nicholas Papadopulos, Dean of Salisbury, said: "We are relieved that the case is over and that a document of Magna Carta's significance is unharmed and remains available to all; we are glad that no one was hurt in the incident; and we are proud of our staff, volunteers and visitors, who acted quickly and courageously."

The court was told Royden has 23 previous convictions covering 51 offences, including theft and criminal damage.

He suffered brain damage in a car accident in 1991 and is subject to a court of protection order regarding his finances, and is aided by a carer.

Salisbury Cathedral's version of the Magna Carta is one of four that remain in existence from the original 1215 charter.

It went back on display three months after the incident, with the damaged case being made part of the exhibition telling the document's history.

Read more: All the latest news from Canterbury

To get the latest updates on ongoing cases, police appeals and criminals put behind bars, click here