Police mounted a guard outside a secondary school after gangs of youths from another school twice stormed the campus.

Seven uniformed officers ringed the gates of Dorothy Stringer School in Loder Road, Brighton, to see children safely into and out of school yesterday.

The police presence was ordered after disturbances at the campus on consecutive days.

On Wednesday a group from Patcham High School marched to the school apparently looking for a fight.

Police were called but no arrests were made.

On Thursday, a group of 10 to 15 youths was spotted approaching the school at lunchtime.

Police said members of the public reported some of the youths were armed with baseball bats, knives and sticks.

However, officers later revised this information saying the youths were not carrying any weapons.

During Thursday's incident, Stringer pupils were kept on the campus while staff, led by headteacher Trevor Allen, confronted the gang at the gates.

When police arrived they broke up the group and talked to the youths.

A 16-year-old was later arrested on public order offences and was bailed on condition he did not go within 500m of the campus.

Inspector Steve Curry said he believed both incidents were connected to a girl/boy relationship.

He said: "The incident was orchestrated by one individual and stirred up by protagonists who called others on their mobiles and in some cases, intimidated them into joining in.

"In terms of what we are used to dealing with as response officers, this was very minor but it needed to be dealt with robustly.

"It was not a huge riot. It is not the first time children have decided to shake their feathers."

He said the response from Mr Allen and Mrs Elizabeth Fletcher, head of Patcham High School, was "absolutely appropriate".

He said: "I have seen them both and it was made clear to me our presence at the school was welcome.

"It is a wholly appropriate response. Children should feel safe and teachers reassured."

After Thursday's incident Mr Allen said there was no conflict between the two schools.

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

Headteacher Andy Schofield brought in private minders after police failed to respond to a 999 call when a man with a knife reportedly entered the grounds.