Fire investigators believe a serial arsonist or gang could be at work after a second Plymouth school caught fire within a week.

A mobile classroom and a shed were destroyed in two separate fires at Widey Court Primary School on Saturday and Sunday.

The attack follows a huge blaze at another city school, St Boniface College in Manadon, the week before.

Investigators have said they fear if another school is attacked, somebody will be injured.

It's a shock, we're sickened by it

Headteacher Mike O'Sullivan

Sniffer dogs and fire investigators have been at the scene at Widey Court school.

One mobile classroom was destroyed and a second was badly damaged in Sunday night's blaze.

But firefighters had also been called to the school on Saturday night, when a shed containing play equipment was razed to the ground.

The school was closed on Monday while investigators examined the scene.

'Loss of resources'

Headteacher Mike O'Sullivan said: "It's a shock, we're sickened by it.

"We're sickened by anything that damages a learning environment for the children in our community.

"We're sad because of the loss of the time, the loss of resources for our children, our parents, our families."

Police are already treating a fire at St Boniface College as arson.

The cost of the damage on 13 October has been put at more than �100,000.

A temporary classroom block was destroyed in the blaze.

CCTV footage

Firefighters managed to stop the blaze spreading to the main school building.

It was the fifth time the school had been vandalised in two months.

Bill Grantham of Devon Fire and Rescue Service said: "The fact there have been three fires would indicate somebody is getting more confident in undertaking these escapades.

"It's only a matter of time before there's a more serous fire in a school and somebody gets hurt as well."

The police are appealing for help from local people in tracking down the arsonists and hope CCTV film footage will identify who was responsible.