Arsonists torched four classrooms and caused thousand of pounds worth of damage in the latest fire attack on a school.

Flames were seen shooting 20ft into the air as two of the first-floor classrooms at Bayards Hill Primary School in Waynflete Road on Oxford's Barton estate were gutted in the blaze.

Twenty-five firefighters were called to fight the fire, which also damaged two other classrooms. Four rooms used as a store for the county's music service were waterlogged.

The school, which has 320 three- to 11-year-old pupils, was closed yesterday, but teachers and parents are working to get it re-opened on Monday.

Police were yesterday investigating the fire at the school, and an arson attack on a sports pavilion in Margaret Road, Headington. The two incidents are being linked.

Headteacher Keith Ponsford said Thursday night's fire was "totally depressing".

He added: "Two of the four classrooms were gutted and the other two were filled with smoke.

"Textbooks and children's work have been destroyed and they are going to be very upset by this. Books are flammable and what was quite extraordinary when firefighters were raking out the cupboards was that you could still see sparks smouldering in the textbooks."

The school's site manager Sally Pether was one of the first people to arrive following the blaze, as her husband Philip, the caretaker, is one of the keyholders who were alerted by the alarm company.

She said: "I went into the instruments store for the music service and unfortunately it has been badly waterlogged."

But Dick Hallam, head of the county's music service, said it had a lucky escape.

He added: "There are three harps, 60 African drums and about 200 violins, clarinets and trumpets stored there, but because of the concrete floors, the vast majority, if not all, have been protected from fire and water damage, so we are very relieved."

Mike Parkinson, chairman of governors, said: "The important thing now is that we get the school up and running as soon as possible."

Tony Prosser, Oxfordshire Fire Service's incident commander, said: "Luckily the school building is quite old, and the concrete construction has helped to minimise the damage."

Tim Wiseman, a police spokesman, said the arsonists broke into the school after cutting through padlocks on security gates.

The fire at the sports pavilion in Margaret Road damaged the inside of the building and the roof after intruders forced the doors.

Dc Miranda Moore, of Oxford CID, said: "These arsons have not only caused thousands of pounds worth of damage, and required a lengthy response from the fire service, but could also have spread, and put people at further risk."

Anyone with information is asked to call Dc Moore on 08458 505505, or Crimestoppers on 0800 555111.