One of Nigel Farage’s closest aides faces years in a US jail after allegedly being caught in an FBI sting.

George Cottrell was arrested and led away in handcuffs as he and the former Ukip leader got off a flight in Chicago.

Cottrell, who runs Mr Farage’s private office, is in custody awaiting trial on 21 charges including attempted extortion, money laundering and fraud.

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Facing jail: George Cottrell was arrested by the FBI after allegedly offering to launder drugs money

The 22-year-old, whose former glamour model mother once dated Prince Charles, is accused of offering to launder money for drug traffickers after advertising his services on the ‘dark web’ – websites that offer privacy because they cannot be traced and need special software to access, some of which are frequented by paedophiles, criminals, hackers and terrorists.

But the ‘drug traffickers’ he is alleged to have dealt with were undercover FBI agents.

Cottrell, grandson of late Yorkshire landowner Lord Manton, was arrested last month as he and Mr Farage were returning from a series of engagements at the Republican Convention in Cleveland, Ohio.

A trusted member of Mr Farage’s inner circle, Cottrell had just agreed to take on a permanent role organising the Ukip MEP’s diary and dealing with media inquiries.

His email accounts, which include details of many of Mr Farage’s day-to-day arrangements, have been frozen.

Court documents filed in the US allege that Cottrell was offering money laundering services on the dark web using the alias ‘Bill’.

When contacted in 2014 by FBI agents pretending to be drug traffickers, he promised to launder their cash for a fee in ‘complete anonymity and security’ through his offshore accounts, the documents claim.

Following a meeting with the undercover agents in Las Vegas, Cottrell arranged for them to send him £15,500, which he planned to pocket, the indictment alleges.

He is alleged to have then attempted to blackmail the ‘drug traffickers’ by demanding £62,000 in the form of bitcoin – a virtual online payment system – saying he would alert the authorities if they refused.

Cottrell was believed by associates to be worth £250million through a family trust fund and had been working for Mr Farage for free.

A trusted member of Nigel Farage’s inner circle, Cottrell had just agreed to take on a permanent role organising the Ukip MEP’s diary and dealing with media inquiries.

But the court documents claim he had a ‘serious, years-long gambling problem, which inherently suggests a strong possibility of irrational risk taking’.

The US District Court in Illinois remanded Cottrell in custody while criminal proceedings continue, ruling that he posed a ‘serious flight risk’.

The detention order filed in the court said that Cottrell had recently changed his name, which he claimed was to distance himself from previous involvement in political activities in the UK, an explanation the court did not find ‘credible’.

Cottrell also claimed he lived with his parents near Evesham, Worcestershire, despite being listed as living at a £2.5million flat in Kensington, West London.

His mother, Fiona Cottrell, was the Penthouse ‘pet of the month’ in October 1973, under the pseudonym Frances Cannon, describing herself as ‘daughter of a landowner’.

The images were reprinted in the magazine in 1977 after she was linked romantically to Prince Charles.

Cottrell’s uncle is Lord Hesketh, a colourful hereditary peer who set up a Formula One team in the 1970s and was a Tory minister under Baroness Thatcher.

A former Conservative Party treasurer, he defected to Ukip in 2011. Cottrell was expelled from the exclusive Malvern College before sitting his A-levels.

He did not complete his education, deciding to go straight into what he has described as ‘private banking’.

His arrest came three weeks after the Brexit victory in the EU referendum, as he accompanied Mr Farage to talk to US media about Brexit.

They flew from London Heathrow to Chicago’s O’Hare airport, from where they had a connecting flight to Cleveland.

Cottrell's mother once dated Prince Charles

As they arrived in the US, Cottrell was briefly detained by customs officers in Chicago in what appeared to be a routine check before being allowed to continue his journey.

He and Mr Farage spent three days at the Republican Convention, where they had a packed schedule of television appearances and meetings with US senators as well as discussions with aides to presidential candidate Donald Trump.

It now appears that Cottrell was being watched by FBI officers throughout the trip.

To Mr Farage’s shock, five FBI officers were waiting to meet Cottrell as they disembarked from their return flight from Cleveland to Chicago O’Hare on July 22, en route to Heathrow.

The distressed former Ukip leader – who knew nothing of his aide’s alleged illegal activities – was given no information about Cottrell’s arrest, and was forced to return to London without him.

The FBI has frozen all Cottrell’s email accounts, leaving Mr Farage without access to his electronic diary. Four days after he was seized, Cottrell appeared briefly in court in Chicago.

An FBI spokesman in Ohio confirmed that George Swinten Cottrell was arrested on July 22 and was due to be extradited to Phoenix, Arizona.

A Ukip spokesman said: ‘George was an unpaid and enthusiastic volunteer for the party over the period of the referendum.

‘We are unaware of the details of the allegations excepting that they date from a time before he was directly involved in the party.’