Two burglars have been told they will spend a “substantial period in prison” after admitting beating a lecturer to death.

Father-of-two Lawrence Hart, 53, was attacked after he left his flat on college grounds and went to investigate a disturbance in the car park. The intruders were high on a cocktail of heroin, cocaine, diazepam and cannabis when they were confronted by Mr Hart and a colleague on August 18, 2005.

Mr Hart was struck on the back of the head and suffered a fatal blow as he hit the ground. He died later of a brain haemorrhage.

College caretaker John Jordan, 52, who went to investigate the disturbance with Mr Hart, was also beaten and needed hospital treatment for his injuries.

Darren Botchett, 33, and Ian Richards, 29, both of Gloucester, appeared at Bristol Crown Court, where they pleaded guilty to manslaughter. They had been arrested soon after Mr Hart’s death. Richards also admitted one count of attempted burglary and one of burglary. Botchett admitted causing grievous bodily harm, theft, and burglary.

Police say the pair have “at least” 50 convictions each - mostly offences committed to feed their drug habits.

Botchett had been released from custody two days before the killing when he was given a community punishment order for theft and other offences.

The attack happened at Hawkwood residential college, near Stroud, at 9.25pm.

Detectives say Mr Jordan heard the burglars inside the building and asked Mr Hart to join him as he confronted them. They then followed them out to the car park.

Mr Jordan also had pound;55 stolen from his pocket as he lay bleeding on the ground.

The court heard the attackers had tried to break in to the nearby Painswick Hotel earlier that evening.

Nicholas Atkinson, prosecuting, said: “It is clear that these two defendants went out burgling, by their own admission of what happened. They were clearly at the college to burgle and, when disturbed, they were determined to escape.

“Mr Jordan was really shaken up, badly beaten, bruised and knocked about.

These are both professional burglars and on this occasion they stepped further when confronted.”

The court heard that Botchett had a “long list of previous offences, two involving violence”.

Mr Justice David Lloyd Jones adjourned sentencing.

He told the defendants: “You must understand that you have pleaded guilty to very grave offences and a substantial period in prison is inevitable.”

Speaking after the hearing, Detective Chief Inspector David Sellwood, of Gloucestershire police, said: “The two defendants are well known to us.

“They have 40 or 50 previous convictions each for dishonesty offences such as theft, all committed to fuel their drug habits.

“We are glad they will be behind bars for a long time.”

Hawkwood college, housed in a 19th-century country manor house, is used for residential courses, including arts, music and personal development.

It describes itself as a “residential centre of learning in the beautiful and peaceful Cotswolds”.

Mr Hart, who lived in a flat on the 42-acre college site, worked as an occasional duty manager and taught meditation twice a week.

His ex-wife Celia Hart and former partner Julia Christie described him as a resourceful and talented man who touched many lives with his enthusiasm, dedication and commitment.

Mr Hart had two children, James, 25, and Rosie, two. He attended Bournemouth grammar school and studied at the London School of Meditation.

His brother, Jan, is an FE Focus cartoonist.

Mr Hart was involved in a project to build a meditation centre in the grounds of Hawkwood.

Katie Lloyd, development co-ordinator at Hawkwood college, said: “We want to remember Lawrence in a positive light and not have to relive the details of the case.”

The college intends to stage a retrospective exhibition of Mr Hart’s paintings.