Organic farmer John Letts, 58, and former Oxfam fundraising officer Sally Lane, 57, sent – or tried to send – sums totalling £1,723 after their son Jack Letts travelled to Syria at the age of 18.
Judge Nicholas Hilliard QC sentenced the pair to 15 months’ imprisonment suspended for 12 months
The couple, from Oxford, denied three charges of funding terrorism. They said outside the Old Bailey: “We have been convicted for doing what any parent would do if they thought their child was in danger.”
Letts, a father-of-one now aged 23, converted to Islam at the age of 16 and had attended a mosque in Cowley Road, Oxford.
Prosecutor Alison Morgan QC said the couple, from Oxford, “turned a blind eye to the obvious” – that their son had joined the murderous terrorist group by the time they sent £223 in September 2015.
The defendants claimed their son, who suffers from obsessive compulsive disorder, was trapped in Raqqa and by December 2015 when they tried to send more funds, they were acting under “duress” fearing he was in mortal danger.
A jury deliberated for nearly 20 hours to find the defendants guilty of one charge of funding terrorism in in September 2015 but not guilty of the same charge in December 2015.
Jurors were discharged after they were unable to decide on a third charge relating to an attempt to send money in January 2016.
Morgan said the Crown would not seek a retrial and asked for the charge to lie on file.
There were gasps in the public gallery but defendants made no reaction in the dock.
The court had heard how Jack Letts left the family home in May 2014 and embarked on what his parents saw as a “grand adventure” to learn Arabic in Jordan.
Before his departure, a friend of the teenager had tried to warn his parents about his growing extremism and urged them to confiscate his passport.
From Jordan, Jack Letts moved to Kuwait and married Asmaa, the daughter of a tribal elder, in Iraq before travelling on to Syria.
Lane told jurors she was “horrified” when he rang her to say he was in Syria in September 2014.
She said: “I screamed at him, ‘How could you be so stupid? You will get killed. You will be beheaded’.”
John Letts begged his son to come home, telling him: “A father should never live to see his son buried.”
He went on to accuse him of being a “pawn … helping spread hatred, pain, anger, suffering and violence”, jurors heard.
Detective Chief Superintendent Kath Barnes said the couple’s conviction sends a clear message, adding: “It’s not for us to choose which laws to follow and which not to and when it’s OK to break the law.”
She said investigators had a “huge empathy” for the Letts family, adding: “Fundamentally John Letts and Sally Lane are not bad people.
“It’s hard to imagine the kind of agony they must be going through because of the choices their son made.”
The jury was not told that father-of-one Letts is being held by Kurdish authorities in northern Syria accused of being a member of IS.