A ninth suspect has been arrested in connection with an arson attack on Jewish community ambulances in Golders Green.
A 48-year-old man was detained in East London yesterday and was taken into custody.
Four Hatzola ambulances were set alight in the early hours of March 23 in front of a synagogue in Golders Green.
The firebombing caused gas canisters stored in the ambulances to explode, with the force from the blast causing windows to break in a block of flats close by.
The synagogue, one of Europe's oldest, had its roof damaged and stained glass windows smashed in the fire.
Three men and a youth have previously appeared in court accused of destroying the ambulances.
The Met Police said 31 people have now been arrested in connection with the attack on the Hatzola Ambulances in March and a number of subsequent arson attacks and incidents.
Of those arrested, eight people have been charged, including a 17-year-old boy who pleaded guilty to arson in connection with an attack at Kenton United Synagogue in Harrow on April 18.
A 19-year-old man arrested in Portsmouth on May 7 on suspicion of attempted arson has also been bailed until a date in July.
Ambulances from Jewish volunteer-led service Hatzola (pictured) were set on fire in the early hours of March 23 outside a synagogue in a suspected anti-Semitic hate crime
The firebombing caused gas canisters stored in the ambulances to explode (pictured, in the aftermath), with the force from the blast causing windows to break in a block of flats close by
CCTV footage captured three hooded figures (pictured) appearing to pour accelerant on the vehicles before setting them alight
Commander Helen Flanagan, head of CTP London, said: 'The attack on the Hatzola ambulances caused considerable community concern and we have been working continuously to investigate this incident.
'Our aim is to arrest and charge all those responsible for the arson attacks and other incidents targeted at Jewish, Israeli and Iranian sites in recent weeks.'
Commander Flanagan added: 'Counter-terrorism officers are also working closely with our Metropolitan Police colleagues to provide protective security advice and support to various organisations, community venues and businesses.
'With the threat level now raised to severe, everyone can play their part to keep themselves and their communities safe. If you have concerns about someone behaving suspiciously, please report it to us. Your information could help us save lives.'
The Metropolitan Police announced this week a new dedicated Community Protection Team of 100 extra officers that will provide a more visible, intelligence‑led and coordinated presence focused on protecting Jewish communities across London.
The Met said the new team is a combination of neighbourhood policing, specialist protection and counter terrorism capabilities.
The most recent incident was an arson at a former synagogue in east London on Tuesday.
Prime Minister Sir Keir Starmer condemned the attack as 'deeply shocking' in the aftermath.
He said: 'My thoughts are with the Jewish community who are waking up this morning to this horrific news.
'Antisemitism has no place in our society. Anyone with any information must come forward to the police.'
Gideon Falter, chief executive of Campaign Against Antisemitism, said: 'We are absolutely heartbroken that this is how low Britain has sunk.
'This horrific act truly plumbs new depths.'
The volunteer-run Jewish organisation Hatzola, founded in 1979, provides free emergency medical response and transportation to hospitals.