A Belisha beacon was an amber-coloured globe lamp atop a tall black and white pole, marking pedestrian crossings of roads in the United Kingdom, Ireland and in other countries historically influenced by Britain. The flashing light warned motorists that this was a pedestrian crossing.
It was named after Leslie Hore-Belisha, the Minister of Transport who in 1934 added beacons to pedestrian crossings, marked by large metal studs in the road surface. The first one became operational on July 4, 1935.
These crossings were later painted in black and white stripes, thus are known as zebra crossings. Legally pedestrians have priority (over wheeled traffic) on such crossings. (I believe they’ve been replaced over the years by WALK signals for pedestrians.)
This little incident apparently happened not long after Belisha beacons were set up in London. The King and his Queen were enjoying a pleasant drive through the city in the royal limousine when they passed an intersection where one of these lights had been installed.
“Pull over up ahead,” King Edward instructed their chauffeur. Then his said to his wife, “I want to try walking across at one of these crossings and see how it actually works.”
The chauffeur stopped the car and the King got out. He walked back up the street to the crossing and about five minutes later he returned.
As he climbed back into the car he was chuckling. The Queen looked at him curiously and asked, “What’s so amusing?”
He grinned at her. “One of my loyal subjects just called me a doddering old fool.”