A 17-year-old Brent boy pleaded guilty to committing arson not endangering life against the Kenton United Synagogue, the Metropolitan Police announced on Tuesday evening, the first conviction in a series of arsons against Jewish sites in the London area.
The British national had been charged on Monday and was the second person arrested for the Saturday attack, which caused smoke damage to the synagogue's interior.
The boy was released on bail under "strict" conditions, including monitoring, until his next court appearance in June.
"This is a significant development, being the first conviction in relation to one of the recent spates of arson attacks on Jewish, Israeli or Iranian-linked venues," Senior National Coordinator for Counter Terrorism Policing Deputy Assistant Commissioner Vicki Evans said in a statement.
A 19-year-old was arrested at another address in relation to the incident and released on bail until May.
Since the March 23 arson of four Hatzola ambulances in the Golders Green area, 23 people have been arrested and eight charged. Thirteen others are in custody or on bail but under investigation.
Seven of those arrested were part of a suspected conspiracy to commit a new attack, but the target was not known.
London faces spate of arson attempts, fire-bombings
Following the fire that destroyed the vehicles of the Jewish community-backed volunteer emergency service, the London area has seen a spate of arsons.
On Wednesday, arsonists attempted to attack the Finchley Reform Synagogue by placing bottles with accelerant next to the synagogue and throwing a brick at the synagogue.
Later that day, an arson attempt was made against the office of Iran International, with suspected arsonists throwing a burning container into the car park of the news outlet. The fire died out on its own.
A building that was once the premises of a Jewish group, still with the organization's name on the window, was the target of a Friday arson attempt. Three bottles containing accelerants were placed next to a building and set alight. The bottles failed to fully ignite, but minor damage was caused to the shopfront.
The same day, jars with an unknown substance, later revealed to be non-hazardous, were discovered near the Israeli embassy.
Harakat Ashab al-Yamin al-Islamia (HAYI), a suspected Iranian front group that has claimed responsibility for many of the attacks.