Pupils held at gunpoint in Tabora region of Tanzania (friel/Flickr)

A group of British schoolchildren have been robbed at gunpoint while on a trip to Tanzania.

The 16 pupils, aged between 15 and 18, were ambushed by a gang of gunmen, who forced them and school staff from their vehicle in the Tabora region.

Gunmen took money, cameras and mobile phones from the pupils, with the gang riffling through their belongings during the holdup.

Nobody was hurt in the attack, but headmaster John Weeds said they had been shaken and suffered emotional stress from the incident.

The students were from the private Cranbrook School in Kent and the trip to Africa was an annual event the school had run for 30 years.

As part of the trip, students worked alongside local people on aid-related projects so they can learn about Tanzanian culture.

Following the ambush, which took place last month, the British High Commission in Dar es Salaam was informed of the incident and a police escort was assigned to them for the remainder of the four-week trip.

Weeds said the attack had not deterred the school from running the trip: "The vehicle was not targeted, and there were a number of other local people in the same queue of traffic involved. It wasn't just about the students.

"The students were fine. There is no accounting for the emotional effect of such an episode as that is difficult to diagnose, but they came back in high spirits.

Four arrested

"We will review what happened but we are very enthusiastic about sending our students to the developing world. It's a very valuable way of broadening horizons. It gives some experience of a completely different environment in a controlled way."

Four men were arrested for the attack: "We understand that the police have got to the bottom of who was responsible," Weed said.

News of the robbery follows another attack on the British students Katie Gee and Kirstie Trup, who suffered from burns when acid was thrown at them by two men in Zanzibar.

Police have since arrested two suspects for the attack, both released on bail. Trup said she plans to return to the Indian Ocean island to ensure her attackers are brought to justice.

According to the Mail & Guardian, the Tanzanian government said it plans to crack down on acid sales to prevent similar attacks by recording the personal details of purchasers.

Ali Mbarouk, the Tanzanian minister of information, culture, sports and tourism, added: "Tourism is the lifeblood of the semi-autonomous Tanzanian island. We have to work harder to make sure that Zanzibar is safe for visitors and ­citizens."