Hans Rausing, one of Britain's richest men, has pleaded guilty to a charge of preventing the lawful and decent burial of his wife Eva's body after she lay dead for up to 8 weeks.
Rausing also admitted driving a vehicle while unfit through drugs.
Police discovered the body of mother-of-four Mrs Rausing in an advanced state of decomposition after they arrested her husband - heir to the Tetra Pak millions - on suspicion of driving under the influence of alcohol or drugs on July 9.
A post-mortem examination established that she died on May 7 and had drugs in her system, including cocaine, Isleworth Crown Court, in west London, heard.
Hans Rausing, pictured here with wife Eva, has pleaded guilty to failing to bury her
Her decomposing body was found in a fly-filled room in their luxury London home hidden under a pile of clothing and bin bags which had been taped together.
The court heard that Rausing was traumatised after her death. He told police in a statement after his arrest: "I do not have a very coherent recollection of the events leading up to and since Eva's death. Safe to assure you that I have never wished her or done her any harm."
Rausing said he understood "with the benefit of hindsight" he had not been acting rationally.
"I tried to carry on as if her death had not happened and batted away any inquiries about her," he said.
"I believe, in the period since Eva died, I have suffered some form of breakdown."
Alexander Cameron QC, David Cameron's brother, defending Rausing, said he had committed the offence "when as Shakespeare would put it, the balance of his mind was disturbed".
He aded that things started to "go wrong" for the couple at the turn of the Millenium. "Things started to go wrong about 1990 to 2000 when the total abstinence of the rehabilitation programmes were mildly lessened by Eva’s urge to have a glass of champagne on New Year’s Eve."
A psychiatrist's report had found Rausing was suffering feelings of severe anxiety and "feelings of inferiority and a tendency to medicate his anxiety by drug taking and a tendency to deal with his emotional conflict by denial".
Their relationship was a "very loving one", he said.
"They were a very loving family unit and they were described by those who worked for them as extremely down to earth people and nice to work for", he said.
Mr Cameron said Rausing had felt "numb and paralysed" when he found her dead.
"He has no recollection of the next 10 to 12 hours, he did not move the body, he described her ... as looking quite restful.
"He felt quite unable to face up to the fact that she had died, almost like a small child, he could not face up to telling anyone else that she had died."
Mrs Rausing, 48, one of Britain's richest women, was found beside a bed in an annexe on the second floor of the opulent house in Cadogan Place in Chelsea, which she shared with her 49-year-old husband.
Bearded and bespectacled, Rausing, whose family made a fortune when they sold the Tetra Pak drinks carton business in the 1990s, has been on bail since his arrest.
Bail was granted on condition that he reside at the Capio Nightingale Hospital, a private hospital in London, and only leave the building accompanied by a member of staff.
Both Rausing and his wife had a long history of drug abuse.
In 2008 they were investigated by police over drugs but the prosecution was formally discontinued.
Rausing, heir to a £5.4 billion fortune from his Swedish father's business, was charged with drugs offences after police found crack cocaine, cocaine and heroin during a search of his home.
After lengthy discussions between his legal team and prosecutors, he accepted a conditional police caution instead.
Neither Rausing nor his wife, who also faced drugs charges, was at City of Westminster Magistrates Court that August to hear that the prosecution had ended.
The couple were arrested in April that year after Mrs Rausing was caught with drugs as she tried to enter the US embassy in London.
Court documents revealed that Mrs Rausing, then 44, was carrying about 10g of crack cocaine, 2.5g of heroin and 2.35g of diethylpropion, a banned stimulant and appetite suppressant.
A further drugs stash - 220mg of diazepam, used to treat anxiety - was also found in her Renault Clio car.
The couple's townhouse was subsequently searched. Officers found 5.63g of crack cocaine, 2.9g of heroin and almost 52g of cocaine.
The conditional cautions, administered by a senior local officer, meant the couple admitted possessing the drugs.
In his prepared statement to the police, Rausing said: "I fully understand that my wife of 19 years is dead and I am devastated, particularly for my children, by her death."
Mr Cameron told the court that a psychiatrist's report had showed an "overwhelmed" Rausing would have been "extremely traumatised and extremely frightened" when he found her body.
"What followed seemed to be a reaction of overwhelming emotional trauma," he said.
Rausing is said to have told the psychiatrist: "I know it is selfish but I just didn't want her to leave."
The court was told that no further charges would be brought in relation to the incident.