No patients were on board the emergency vehicle as it was travelling between Alconbury and Sawtry at 12.30am this morning (Thursday, November 29) but firefighters had to cool and remove several oxygen cylinders which were inside. A spokesman for the East of England Ambulance Service praised the crew members who were on board at the time and escaped from the incident uninjured. He stressed there had been no delays in responding to any patients as a result of the fire, as back-up was provided from other sources. An investigation is now taking place by the ambulance service into why the vehicle caught fire. Cambridgeshire Fire and Rescue said the cause was accidental and that it took one jet and one hose reel to extinguish the blaze. Two fire crews from Huntingdon, a crew from Sawtry and a water carrier from Yaxley were called to the incident and returned to their stations by 2.55am.