A family from Sutton found themselves under aerial bombardment when a block of ice dropped out of the sky and flattened their garden shed.
Lloyd Gater, 32, and his partner were sitting at their kitchen table when they heard a thunderous crash outside their home in Stayton Road.
It emerged that a frozen chunk of water the size of a potable TV had fallen from the leaking toilet system of an aircraft passing overhead.
Mr Gater, a father of two, was stunned by the bolt from the blue. "I just thought bloody hell, what was that'. I went out into the garden and saw the shed had been wrecked," he said.
"It was crazy. There was ice scattered along the floor. You could see where it had come through the trees. I started to realise it was probably from an aeroplane.
"The ice could have hit surrounding houses and caused much more serious damage. I spoke to my insurance company, who were a bit surprised."
This week Civil Aviation Authority (CAA) investigators admitted the chances of identifying the aircraft responsible were slim.
Experts poring over radar recordings would need to analyse aircraft altitudes, wind speeds and the trajectory of the plummeting object.
The CAA fields about 35 reports of falling ice each year. Most involve football-sized lumps of frozen effluent, dubbed "poodlebugs", that drop from fuselages when planes descend into warmer air.
A spokesman said: "We try to trace the aircraft in the area at the time and ask them to check their onboard systems for faults."
Other reported cascading objects have included nuts, bolts and the body of a teenage stowaway, who fell from his hiding place as a jet travelling from India lowered its undercarriage. The corpse narrowly missed a primary school in Richmond, south-west London.