Bobby Finders

In 1903, a London businessman by the name of Alfred Dunhill became one of, or possibly was, the very first motorist to be prosecuted for speeding. ( he had, it is said, the third motor-car ever to arrive in Britain) The speed-limit in all of Britain was then 12 miles per hour. Alfred's car was seen by a policeman doing the unthinkable speed of twenty-five miles per hour. Alfred was fined the sum of one pound. The charge was 'driving furiously'.
Irate, and incensed by this injustice, as he saw it, he decided to work to obstruct the police, and abet the motorist, and very soon was advertising 'Dunhill's Bobby Finders', (Bobby being a slang term for a policeman).His device was a pair of binoculars, which were fitted to driving goggles, and hinged, so they could fold up, or be brought down to see the road ahead.His slogan was "Will spot a policeman at half a mile -even if he is disguised as a respectable man."
An early fore-runner of the radar warning devices, and speed camera alerts.

A similar device in Portugal in 1914 was blogged at Gatochy's Blog yesterday, though that looks to be aimed more at the theatre or opera enthusiast.