LONDON (AFP) - A woman accused of trying to smuggle €20,000 (S$33,000) in cash hidden in her underwear to jihadists fighting in Syria was found not guilty by a British court on Wednesday.

The 11-person jury at London's Old Bailey found Nawal Msaad, 27, not guilty of funding terrorism, but convicted her friend Amal El-Wahabi, who allegedly used her as a "trusted courier".

Msaad was stopped at London's Heathrow Airport and found to have the cash in notes wrapped in a condom that prosecutors alleged fell into her underwear after being lodged inside her body.

El-Wahabi's husband, Aine Davis, had asked for the money after leaving Britain in July 2013 to join Islamist militants fighting in Syria, the court heard.

Both women denied the charge of providing money with "reasonable cause to suspect that it would or may be used for the purposes of terrorism".

El-Wahabi, 27, is the first Briton to be convicted under terror laws of funding jihadist fighters in Syria after being found guilty by a majority of 10-1, and now faces up to 14 years in jail.

She sobbed uncontrollably as the verdict was revealed, saying: "I can't breathe, no, I can't breathe."

Prosecutor Mark Dennis earlier told the court that Msaad was stopped at Heathrow on January 16 and told police she was flying to Istanbul to buy gold for her mother.

"She was then taken to a private room where she pulled out a roll of banknotes from inside her underwear and handed it across to the officers. The banknotes were tightly rolled and were wrapped in cling film," Dennis added.

"It would appear that it would have been further hidden inside her body, wrapped in a condom."

Msaad, who was studying at a London university at the time, denies the claim, saying the roll was lodged in the waistband of her leggings and that she had voluntarily told police she was carrying the money.

She was allegedly offered €1,000 by El-Wahabi to act as a courier, and claims her friend had not told her what the money was being used for.

Prosecutors say the trip was arranged in a string of phone calls and WhatsApp messages between Msaad, El-Wahabi and Davis.

Dennis claimed the money "had been raised in this country and had been destined to support the jihadist cause which Davis was now pursuing with like-minded supporters".