class="story-body__introduction">An aircraft and a helicopter have crashed in mid-air over Buckinghamshire, with a number of casualties reported, according to BBC.Emergency services were called to the site at Waddesdon Hill, near Waddesdon Manor, near Aylesbury, at 12:06 GMT. The Air Accidents Investigation Branch (AAIB) has sent a team to investigate. A Wycombe Air Park spokesman said both aircraft came from the airfield near High Wycombe. The AAIB said the plane involved was a Cessna. South Central Ambulance Service said it received a call for a "mid-air collision" between a helicopter and an aircraft in Upper Winchendon, near Aylesbury. It said: "There have been a number of casualties at the scene, but at this stage this is all we are able to confirm." Thames Valley Police said the priority was "saving lives". Mitch Missen, an off-duty firefighter, witnessed the crash from his garden. He said: "I looked up and saw as both collided in mid-air, followed by a large bang and falling debris. "I rushed in to get my car keys and en route called the emergency services, who I continued to give updates as to its whereabouts. "Unfortunately, I wasn't able to locate the actual crash site but directed police, fire and ambulance as best I could. Once they were on the scene, I returned home." There were a number of road closures following the crash but they have since been lifted. Seven fire vehicles from Aylesbury, Haddenham, Oxfordshire and Berkshire went sent to the scene. A spokesman for Bucks Fire and Rescue Service said 30 members of staff in fire engines and urban search and rescue vehicles attended. He added: "I understand it is in a wooded area near the manor." The Thames Valley air ambulance, two ambulance crews, two ambulance officers and a rapid response vehicle were also sent to the scene.