Firefighters now assisting other emergency services at scene of a reported crash between an aircraft and a helicopter at Waddesdon, Buckinghamshire. Ambulance crews have reported "a number of casualties".
Fire and ambulance services rushed to the scene at 12:06 p.m. GMT (7:06 a.m. EST) near Aylesbury in Buckinghamshire.
At least seven fire appliances and seven fire officers were deployed as part of the efforts.
Road users are advised to find alternative routes as emergency services attend the scene. My mother said a man, who I think was someone who had been out walking, then came running towards the manor to say there had been a crash.
The plane in the crash is understood to be a Cessna 152.
RAF Halton, which is around 10 miles away, has said no military aircraft were involved.
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Just five minutes earlier she had been picking a plant in the Wilderness Woods, the scene of the crash site, on the Waddesdon Estate.
"We're aware of a number of casualties following an incident this afternoon", Thames Valley Police said in a tweet.
"There have been a number of casualties at the scene, but at this stage this is all we are able to confirm".
Road closed and very slow traffic due to incident involving an aircraft on A41 Both ways between Blackgrove Road and High Street.
Air crash investigators have been called to the crash site, in dense woodland, alongside paramedics, firefighters and Thames Valley Police, who said the first priority was "preservation of life".
Buckinghamshire Fire and Rescue Service said they now have seven vehicles responding to the incident, including fire engines as well as urban search and rescue vehicles.