The 21-year-old man arrested on Saturday by police investigating the terrorist attack at Parsons Green subway station in west London has been named as Yahyah Farroukh, local television report said early Monday.
Queen Elizabeth II awarded the couple for their services to children in 2010.
Following the attack, Amaq, the news agency of the Islamic State militant group, claimed responsibility for the bombing.
Witnesses described seeing him being arrested outside Aladdins Fried Chicken in Hounslow at midnight on Saturday.
Police believe he had just left the home of his foster parents, Ronald Jones, 88, and his wife, Penelope, 71, near Heathrow Airport, and was making his way to catch a train to London, where he planned to unleash terror. The leader of the local authority was quoted as saying the 18-year-old was an Iraqi who had come to Britain as an orphan aged 15. Both suspects were held under the Terrorism Act and questioned at a London police station even as searches continued on Monday at various places.
Ian Harvey, who heads local Spelthorne Borough Council, said he believed the 18-year-old was an Iraqi orphan who moved to the United Kingdom when he was 15 after his parents died and had lived in the Sunbury house. Images after the device detonated on Friday showed it was carried in a Lidl bag. IS claimed credit for other previous attacks, including two in London and one at a concert by American singer Ariana Grande in Manchester.More news: Democrats batter Rick Scott over nursing home tragedy
The 18-year-old was detained Saturday at the southeast England port of Dover, a departure point for ferries to France.
"A forensic team wrapped his arms in plastic up to his biceps and his legs up to his thighs", a witness told the paper. A second property in Hounslow was also being searched. "When they took him down his phone went flying and he dropped his bag containing a drink can and a KitKat".
West Thames College in West London said in a statement that "Yahyah Farroukh, who, according to media reports is the second suspect detained in connection with the Parsons Green incident, was a former student at the college from December 2013 to June 2015".
"The guy was screaming. I guess because it holds important information".
With the arrest of the suspects, the UK Home Secretary Amber Rudd announced that the country's terror treat level, which had been raised to its highest at "critical", would be lowered back to "severe" as "sufficient progress has been made" into the investigation.
"There are now two searches continuing at addresses in Surrey and we are getting a greater understanding of the preparation of the device", he added.