Jewish neighbourhood watch groups have appealed for witnesses after two Jewish boys were physically and verbally assaulted on Sunday.

Shomrim, which organises volunteer patrols, said the incident occurred at around 7.30pm at the North Circular Road crossing between Golders Green Road, NW11, and Brent Street, NW4.

The Shomrim volunteers were able to detain a suspect who was subsequently arrested by police, but say they need witnesses to the attack, and in particular have appealed to a man who stopped his car to help, but who did not leave his details.

“His evidence is extremely crucial to ensure the perpetrator faces prosecution,” said a Shomrim spokesman. “We therefore appeal to this witness and anyone else who witnessed this incident to please make yourself known.”

The group said only that “two young Jewish boys” had been “racially assaulted, verbally and physically”.

Separately on Tuesday morning, the Community Security Trust (CST) said some Jewish schools had received threatening emails. The National Crime Agency said schools across the country had received similar “distressing” communications and that it was investigating, adding that there was “no credible threat”.