A senior aide to former Ukip leader Nigel Farage faces up to 20 years in prison after pleading guilty to masterminding a scam to extort money from drug dealers.

George Cottrell, 22, was arrested in July as he and Mr Farage disembarked from a plane at Chicago O'Hare airport and was extradited to Arizona, where he has been held behind bars since.

Cottrell previously ran Mr Farage's private office and was part of Ukip's media team.

He posed on the so-called dark web as "Bill" where he was contacted by undercover FBI operatives posing as drug traffickers who proposed to send him between $50,000 and $150,000 of drug money each month.

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Court documents said he arranged for the agents to send him £15,500 which he intended to keep for himself.

He then demanded £62,000 in bitcoin and threatened to alert authorities if they refused.

In his plea agreement, seen by The Mirror, he admitted: "I falsely claimed that I would launder the criminal proceeds through my bank accounts for a fee.

"Rather than launder any of the money, though ... I intended to retain the money."

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Cottrell was originally charged with 21 counts of fraud, money laundering and extortion.

After he plead not guilty to all of them, prosecutors agreed to drop all but one, wire fraud, in exchange for a guilty plea.

He will be sentenced in March and could face up to 20 years in prison and a $250,000 fine.

The Ukip aide was expelled from Malvern College before he sat his A-levels and went straight into what he described as "private banking".

He is surrounded by influential family figures, including his uncle Lord Hesketh, who set up a Formula One team and worked for the Thatcher government.

His mother, Fiona Cottrell, was a glamour model and was linked to Prince Charles in the 1970s.