Two children found a shattered propeller which fell off a plane at 2,000ft.

Alexander Hill, four, and his sister Louise, seven, went with their parents to search fields behind their home after hearing the aerobatic display plane's engine cut out as it swooped over their home in Newick.

They discovered half of the metre-long propeller lying in a field. The pilot and his passenger made an emergency landing in the field two miles away in Isfield minutes after farmer Chris Holland had rounded up his cows for milking.

The children's mother, Hilary, said they had been enjoying a family barbecue when they watched the drama and saw an object fall from the stricken plane.

She said: "Our house backs on to the Downs and we often see planes coming over but this was exceptionally low. We heard a bang and then the engine cut out. At first we thought it was a stunt but the children saw an object falling from the plane so we set off to discover what it was."

Their father, David, alerted the Civil Aviation Authority before joining in the search.

Mrs Hill said: "We went across the field and found the propeller lying on the ground."

The aluminium-coated wooden propeller had broken in half and was burned at one end, suggesting it sheared off after an engine fault.

Pilot John Smith, 65, from Wimbledon, and co-pilot James Green, 64, from Eastbourne, had been flying back to Shoreham Airport from a cancelled airshow in Lincoln when the Stampe bi-plane started to misfire over the Thames at 2,000ft.

The CAA said a full investigation into the accident was being carried out.