“Mindless vandals” caused thousands of punds worth of damage by smashing windows and slashes tyres on two school minibuses.
The yobs struck at Central Lancaster High School in Crag Road during the first weekend of the Easter holidays.
Most of the windows were smashed on the school’s two minibuses, and the majority of the tyres were also slashed.
Head Nicola Hall said the damage will cost “a substantial amount of money” to repair.
“It’s mindless vandalism,” she said.
School staff were devastated to discover the damage caused to the school’s two minibuses in the first weekend of the Easter holidays.
The minibuses are used on a daily basis to transport the school’s most vulnerable pupils to school, and also for trips, sporting fixtures and activities.
Mrs Hall said: “It is saddening and sickening to think that someone would choose to deprive school children of vital resources that are used daily.
“The cost of repairs will be substantial and already very stretched school funds will have to be diverted from other activities to pay for these repairs.
“It is shameful that these individuals have a mindless disregard for opportunities for children.”
The school has had many messages of support and it is clear that the community feel upset and angered by what has happened.
Neighbours of the school disturbed the vandals and Mrs Hall added that the school is very thankful for their actions as they may have prevented further damage to school property.
The school is working closely with the police to identify the individuals involved in the vandalism, using CCTV from the scene.
The incident follows a spate of vandalism at The Loyne Specialist School in Lancaster during the February half-term break.
Staff at the specialist school in Sefton Drive were left in shock after young vandals stole bikes worth £4,000 and caused damage including fence paint thrown across a patio area, doors and windows, and sports equipment and gardening tools strewn across the playground.
Tools were also used to gain entry to a cycle store containing several bikes which were stolen.
Among the £4,000 haul were a number of specially adapted scooters, some two-wheel bikes and a unique four-wheel low rider bike which was specially adapted for a Loyne pupil.
Lancaster MP Cat Smith said: “It’s devastating to hear about the damage to the school mini buses – particularly at a time when the Conservative Government is slashing school budgets.
“In a survey I’m carrying out with headteachers in Lancaster, many report they can’t afford to pay for the basics like books, stationary and maintenance, let alone find the cash to repair vehicles damaged through mindless vandalism.
“It’s dreadfully upsetting that the children may lose out on educational activities because they haven’t any transport.”