The Israeli Embassy has criticised the decision to caution a 16-year-old boy who attempted to attack its deputy ambassador at a university campus.

The embassy called for a stricter punishment, saying the teenager had "crossed a line" when he climbed on the bonnet of Talya Lador-Fresher's car and attempted to smash the windscreen. The deputy ambassador said she had feared she would be physically assaulted.

Ms Lador-Fresher had been speaking to members of Manchester University's Politics Society in April. Around 40 demonstrators had gathered at the venue.

The mob ran towards her as she left and she was then escorted through a back door to a security vehicle. But the protesters discovered the evacuation plan and surrounded the car.

Police confirmed a teenager was cautioned for a racially aggravated public order offence and had agreed to a series of conditions on his future behaviour.

He cannot attend demonstrations unless accompanied by an adult; he must keep the police informed about his movements; and he is to be placed under a limited curfew.

But an Israeli Embassy spokesman said: "Unfortunately, despite the efforts of Greater Manchester Police, which we appreciate, justice has not been done.

"Those who attacked the deputy ambassador's car crossed a line between acceptable legal protest and illegal physical intimidation and it is regrettable that their behaviour has gone unpunished.

"We will continue to state Israel's case at British universities with clarity, courage and pride, despite an increasingly hostile, aggressive and threatening atmosphere on many campuses."

Jon Benjamin, Board of Deputies chief executive, said: "The incident following the talk went beyond the realms of the acceptable, if heated, level of debate that had taken place in the lecture hall itself.

"It was clearly right for the police to investigate this matter and we are pleased that they have acted to issue an unequivocal warning to the young man. Activism about Israel on campus has the potential to become intimidating to Jewish students. Universities have to address this as a very real issue."