In 1941 Pilot Officer David Watson was based at RAF Watton, Norfolk, flying Blenheim light bombers. On a training flight over the east of the county, the young New Zealander spotted something strange in the rural landscape: on his return to base he invited his Flight Commander, Peter Meston, to accompany him to investigate further.
Watson had noticed that in several remote areas of Norfolk piles of agricultural lime had been laid out in straight lines, each ending in an arrow-head. It seemed obvious that these apparent pointers had not been made by accident, but rather appeared to have been oriented to indicate large grassy meadows that could serve as landing strips. Next to these in every case were brand-new conspicuously-painted red barns with unusually wide access doors.
Subsequent investigations at a number of Norfolk sites revealed that all farms possessing one of these strange barns were owned by the same property company, the directors of which were Dutchmen with known financial links to Germany. It was also claimed by other pilots that in several cases, chicken hutches at the farms were laid out in the shape of a swastika!
The whole matter was kept secret for sixty years until Meston told his story on television: I carried out my own investigation and discovered that many of these barns still exist, near the villages of Sporle, Beighton, Cantley, Halvergate, Paston, Guestwick and South Repps.
Seventy years later the results of an intensive MI5 investigation have still not been released, but it has been widely accepted that the barns were built to accommodate Nazi glider troops and their aircraft in the run-up to an invasion.