Bernard Madoff, once one of the most powerful men on Wall Street, now shares a cell with a 21-year-old drug offender and eats pizza cooked by a convicted paedophile, according to a new legal filing that offers an insight into the fraudster's prison life.

Joseph Cotchett, a California lawyer, sat with Madoff for a four-and-a-half-hour interview in July, and says he gave details of his new prison associates.

"Rather than spending time on private planes or his yachts, or residing in his luxury apartment in Manhattan, his Montauk, Long Island and Palm Beach mansions, or his property in Cap d'Antibes, France," he says, "Madoff now shares a cell with a 21-year-old inmate convicted of drug crimes.

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"Madoff sleeps in the lower bunk and he eats pizza cooked by an inmate convicted of child molestation. His recreation consists of walking around the prison track at night."

Madoff, 71, is serving 150 years after admitting he ran history's largest pyramid scheme. He agreed to meet Mr Cotchett in an attempt to shield his wife, Ruth, from a legal assault by the attorney's firm, which is suing a slew of Madoff relatives, employees and business partners that it says knew, or should have known, about the scheme that cost investors $65bn (£40bn).

The suit also provides new allegations about what Mr Cotchett says was the unprofessional atmosphere at Madoff Investment Securities in New York, where Madoff was only pretending to invest his clients' money. The fraudster employed "street tough men from Harlem, who were not to be messed with" to bring drugs to the office, and topless waitresses were hired for cocaine-fuelled parties. And, the complaint alleges, drug use was so "rampant" in the office that it was referred to as "the North Pole".