Head teachers today moved to calm fears over security after police were called to break up a disturbance at a school.

Officers were called in after a gang of up to 15 youths carrying sticks arrived at Dorothy Stringer School, Brighton.

Staff alerted police after the group was spotted approaching the school at lunchtime yesterday.

The grounds were sealed and Dorothy Stringer pupils were kept inside while staff confronted the gang.

It was the second time in two days that a group of youths had gone to the school in Loder Road.

Last month Varndean School, which shares the same campus as Dorothy Stringer, drafted in security guards after a knifeman threatened staff.

Head teacher Andy Schofield brought in minders from MAN Security after police failed to respond to a 999 call when an intruder with a knife entered the grounds.

Last night Trevor Allen, head of Dorothy Stringer, said he saw no reason to step up security.

"We were alerted that these boys, who were about 16 or 17, were on their way to the school and senior staff and myself turned out to prevent any problem. We kept our children on site and made sure there was no ingress on the part of this group of boys.

"We contacted the police who came and took some of the boys away."

Mr Allan said he did not see the youths carrying implements of any kind.

On Wednesday a group of youths from Patcham High School arrived "looking for a fight over a girl."

Mr Allen said: "It is difficult to know whether the two things are related. But as far as I know there is no conflict between boys or girls from the two schools. There may be an outside school problem but it is not a school versus school problem."

Mr Allen said he was happy with the way his staff handled yesterday's incident.

"I'm very pleased with the way they dealt with it and our children, who get excited about these things, behaved admirably. I'm proud of them."

He said he would be talking to the other schools on the campus about security but only as part of their routine meetings.

Elizabeth Fletcher, head of Patcham High School, said some of the boys involved yesterday were her pupils and staff went to collect them.

She said: "We have spoken to the students involved and withdrawn their privileges and we have talked to their parents.

"There is competition between the schools but there are not warring factions. These things happen very occasionally between schools. In this case it involves a very small group and with a bit of luck it will die down over the weekend."

Police said reports of youths carrying sticks came from the school.

A spokesman said: "We attended and broke up the groups. The people involved were spoken to but no arrests were made."

Mr Allen and Mrs Fletcher were both commended in recent Ofsted reports for their leadership skills.