Crews who attended the scene at the former Bective Middle School site in Kingsthorpe at about 6pm last night arrived to find a gang of yobs throwing missiles at them.

Meanwhile, Northamptonshire Fire and Rescue watch manager Nick Smith revealed at the scene that CCTV cameras, which were fitted to fire engines six weeks ago, cannot be used because the correct paperwork has yet to be filled out.

He said: "All the equipment is ready to go and we have had CCTV fitted to these appliances, but unfortunately they cannot be used yet for administrative reasons. It's just the paperwork that's stopping us.

He added: "It is frustrating that people behave this way. We are here to protect the community and we do our best, but unfortunately there are those people who just don't see it that way. It comes with the territory these days."

The assault comes just days after the Chronicle & Echo reported an attack on an emergency ambulance crew in Blackthorn, where yobs tried to pry open the doors of the ambulance and damaged the windows.

Bus and train attacked by stone-throwers - click here

PCSO Kirsten Munns, of the Kingsthorpe and Boughton Green SCT, remained at the scene of the fire in Whiston Road to talk to the parents of the children involved.

She said: "There is just no excuse for this sort of behaviour, it's disgusting. People can rest assured the children will be dealt with and letters will be sent to all of their parents so they know what the children have been getting up to.

"We're talking about youngsters who were all under the age of 15, and this was the sort of behaviour I only expect to happen outside of Northamptonshire."

Councillor Terry Wire (Lab, St James), a former firefighter who campaigned to have CCTV cameras fitted to engines following a spate of attacks, said the youths' behaviour was "despicable".

He said: "It has to be condemned. These firefighters are there to protect the public, and it only takes one injury for their resources to be depleted.

"I will be asking the question as to why the CCTV cameras are not working yet, because it is incredibly frustrating that the machinery is all there waiting to be used."