The Priory, Roehampton, was built in 1811 as a private home and turned into a hospital in 1872. It is London's oldest private psychiatric hospital.
The Priory Group, which owns the famous Roehampton clinic, has 42 hospitals and teaching schools in the UK. It also runs specialist centres for children with autism and other mental health issues.
Gambling, sex, drugs, alcohol and computing addictions are all treated there.
In 2005 the Priory Group was sold to Dutch bank ABN Amro for £875m.
Dr Chaitanya Patel, the former chief executive of the Priory Group, is one of the Britain's richest Asians. A significant donor to the Labour party, he was caught up in the 'loans for peerages' affair. He resigned from Priory Healthcare last month.
Private patients pay around £3,640 a week, but half of the patients at the 107-bed clinic are referred there by the NHS and do not pay. Some are sectioned under the Mental Health Act.
Treatments range from group therapy and electric shock treatment to horse riding and yoga.
In 2004 the MoD signed a three-year contract to use the Priory Group hospitals to treat service personnel. More than 800 servicemen and women suffering post-traumatic stress disorder after serving in Iraq have been admitted in four years.
Famous guests at Priory Group hospitals, include: Kate Moss, Pete Doherty, Robbie Williams, Paula Yates, Ronnie Wood, Eric Clapton, Lady Isabella Hervey, George Best, Ronnie O'Sullivan, Michael Barrymore, Kerry Katona, Jade Goody, Justin Hawkins, Gail Porter, Paul Gascoigne, Caroline Aherne, Sinead O'Connor, Tom Chaplin and Marti Pellow.
Television presenter Gail Porter, who was admitted to the hospital in 2005 following an apparent suicide bid and self-harming, has said of her treatment: 'It wasn't for me. This woman compared me to a car, saying my engine wasn't working properly. I thought, "If I stay here for a week I'll jump out a window".'
Former Darkness singer Justin Hawkins has said: 'I thought I'd go in, do a lap of the grounds and come back out. But I got in there and broke down. I was shaking like a leaf and going through cold turkey. So I joined the month-long addiction treatment programme. It was exhausting. People have this unfair view of places like the Priory as a holiday camp for celebrities. But the work they do there is so important. There were people from all walks of life - housewives and builders. We had nothing in common other than drink and drugs but I made friends for life. I'd love to become a counsellor.'
Britain and addiction: facts and figures
Research from the Royal Society of Arts estimates that England and Wales have between 250,000 and 350,000 'problem drug users' who are regularly using crack, heroin or cocaine.
According to the charity Over-Count, up to 40,000 people in Britain are addicted to over-the-counter drugs.
1.1 million people in England and Wales are considered to be dependent on alcohol and 8.2 million people are said to have an 'alcohol use disorder' (Health Development agency, 2005).
According to recent research, cocaine addiction has tripled in the past 10 years; heroin addiction has quadrupled in the past 15.
A Home Office study estimates the value of the illegal drugs trade in Britain is £4bn-£6.6bn.
Illegal drug use is the third commonest cause of death among 15 to 34 years olds, after traffic accidents and suicide.
300,000 children have parents with serious drug problems (around 3 per cent of children under 16).
Between 780,000 and 1.3 million children are affected by parental alcohol problems (Alcohol Concern, 2003).
£573m was spent on drug treatment by the government in 2005/6.
Research suggests that a heroin addict commits, on average, 432 crimes a year.
In the UK there are about 40,000 heroin users taking methadone to try to beat their addiction.
A report by Glasgow University last year found that fewer than 4 per cent of heroin addicts beat their addiction with methadone.
97,490 people a year claim incapacity benefit and disablement allowance because of drug and alcohol problems.
The estimated number of regular users of heroin, cocaine and synthetic drugs worldwide is 50 million (UN).
A quarter of male hospital beds are taken up by alcohol-related illnesses.
725,000 hospital admissions for mental and behavioural disorders are due to alcohol, including 31,300 for alcohol dependence syndrome (Action on Addiction).
71 per cent of GPs and practice nurses do not know how to treat dependent drinkers (Alcohol Concern).
Deaths in England and Wales from alcohol-related disease have doubled in 15 years (Office for National Statistics).
Research from the Department of Health suggests that more than 20 children and teenagers a day are being treated in hospital for alcohol-related illness.
