Image copyright Reuters Image caption Nigel Farage said he had never had any suspicions about Cottrell's behaviour

An aide to former UKIP leader Nigel Farage is facing up to 20 years in jail in the US after admitting to fraud.

George Cottrell struck a plea bargain with prosecutors, who said he had agreed to launder money for undercover agents posing as drug traffickers.

He was arrested in July as he and Mr Farage were preparing to return to the UK after the Republican convention.

Mr Farage told ITV he was surprised by what had happened and had "never had any suspicions" about the volunteer.

The MEP, who stood down as leader in November, told Good Morning Britain he could not be held responsible for "what everyone around me does".

UKIP says Cottrell was an unpaid volunteer during the EU referendum campaign and the offence dates from before he was directly involved in the party.

After being caught in an FBI sting operation earlier this year, Cottrell - who is in his 20s - faced 21 counts relating to money laundering, fraud, blackmail and extortion.

These were reduced to one count of wire fraud as part of a plea agreement agreed with prosecutors in Arizona last month.

In the plea bargain, Cottrell states he and an associate known as Banker communicated with the "traffickers" in 2014 and talked about ways that "criminal proceeds" could be laundered by transferring large sums of money out of the US and disguising them as "legitimate business income for tax purposes".

In the document, Cottrell - who posed as a "financier" on the internet - says: "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, Banker and I intended to retain the money."

'Bad company'

Prosecutors say law enforcement agencies, posing as traffickers, contacted Banker seeking to launder up to £120,000 a month in drug trafficking proceeds and were then put in touch with Cottrell, who agreed to transfer the funds to offshore accounts with "complete anonymity and security".

They later met Cottrell in person in Las Vegas.

Cottrell was subsequently arrested at Chicago's O'Hare airport in July en route back to Britain after accompanying Mr Farage to the Republic convention in Cleveland, where the British politician spoke at a rally for Donald Trump.

Cottrell is expected to be sentenced in March.

He is also liable to a fine of up to £203,000.

Asked for his reaction, Mr Farage said Cottrell had never been employed by the party.

"He was a volunteer. He was unpaid. He was helping me do stuff. He'd been part of our party for a couple of years.

"We never had any suspicions about him at all. He faced 21 charges in America, 20 have been dropped. He's pleaded guilty to a C-grade felony. Listen, I can't be responsible for what everyone around me does."

He added: "He was 20 years old at the time this happened. Guilt, no guilt, fallen into bad company - I'm not sure."

Cottrell's uncle, Lord Hesketh, is a former hereditary peer, who worked for former Prime Minister Margaret Thatcher before losing his seat in the Lords in 1999 as a result of the House of Lords Act.

The peer later defected to UKIP.