British anti-terrorism investigators have seized £240,000 from an American Muslim activist jailed in the US for illegal financial dealings.
The money was seized at Heathrow Airport
The cash, taken from Abdurahman Alamoudi at Heathrow Airport in August 2003, was forfeited by court order.
The Metropolitan Police say it is the largest single seizure by UK officers of cash intended to fund terrorism.
Eritrea-born Alamoudi is serving 23 years for dealings linked to an alleged plot to assassinate a Saudi leader.
The money, confiscated by two separate orders following hearings at London's Horseferry Road and Uxbridge magistrates courts, will now pass to UK government coffers.
Alamoudi, a prominent figure in American politics, was passing through Heathrow on a connecting flight to Syria from his home in the US when security staff noticed a large amount of cash in his luggage and alerted police.
The suitcase was searched and $336,900 (£180,000) seized under the Proceeds of Crime Act but Alamoudi was released by police, who did not realise the full significance of the discovery.
Later, a further $69,400 (£37,100) was seized from a property in Colindale, north London. Police said Alamoudi had left this cash with an unsuspecting friend who had no idea of its possible purpose.
Both amounts were forfeited at Friday's court hearings.
After the Heathrow seizure, investigations by the UK's National Terrorist Financial Investigations Unit (NTFIU) uncovered a chain of connections between Alamoudi and various Middle East and Libyan-based front organisations suspected of having links with terrorism.
US police, acting partly on information from the UK authorities, arrested Alamoudi at Dulles International Airport in Washington DC when he returned to America in September 2003.
He later admitted offences relating to terror fundraising and was jailed in October 2004.
US prosecutors claimed he had been involved with deals linked to an alleged Libyan plot to assassinate Crown Prince Abdullah - the de facto leader of Saudi Arabia.
Libya has denied backing any such plot.
The NTFIU has rapidly expanded in the wake of the terrorist attacks in the US on 9/11.