Twelve sixth-formers, led by a local retained firefighter, are trained to operate the engine and to tackle burning buildings.
"The unit is on standby in case there is a fire in a school building," said David Harris, bursar at the pound;6,141-a-term boarding school. "They can point the hose at the fire, but can't enter burning buildings, because they're pupils."
Oundle has a rich tradition of extra-curricular activities for sixth-formers. As well as pursuits such as bellringing and croquet, students are given a choice between Combined Cadet Force service, adventure training, or fire and emergency work.
Members of the fire unit train regularly and are skilled at extinguishing dummy fires. They also practise using their fire engine, acquired earlier this year after it was retired from Cambridgeshire fire service. The engine is still fully functional: in fact the school beat a needy fire service in Ireland in the race to buy it.
The skills that the unit teaches, says Mr Harris, may prove useful during the current strike: "We have a retained fire service in Oundle, but they are largely manned by members of the Fire Brigades Union, so we're more likely to be called into service."
But Oundle Council's fire service is less enthusiastic aboutthe idea. "We encourage fire-safety education, but we don't advocate members of the public fighting fires themselves," said a spokesperson.
Local Focus, centre pages