On the A40 at halfway between Llandovery and Brecon there is a memorial to a stage coach disaster. If your speed is as unrestrained as that of the coach driver you could miss it. There is an obelisk enclosed by iron railings, next to a busy road. At the bottom of a steep slope on the other side of the road the Afon Gwydderig rushes and roars just as it did in 1835. On some maps it is marked simply by the word Memorial. But that single word does not do justice to the surprising nature of this simple pillar that stands under the trees in a dark lay-by.So what is it?It is one of the earliest warnings against drink-driving, thats what it is. It is called the Coachmans Cautionary.It marks the spot where the Gloucester to Carmarthen coach plunged off the road and down a precipice on 19 December 1835. According to the inscription the driver, Edward Jenkins was intoxicated at the time and drove the mail on the wrong side of the road ...at full speed or gallop. The coach went over the precipice 121 feet where at the bottom near the river it came against an ash tree when the coach was dashed into several pieces. Obviously Jenkins was the single common ancestor of White Van Man.The memorial was erected as a caution to mail coach drivers to keep from intoxication. Quite right too in my view. No one should ever be asked to entrust their life to a man in charge of a bottle, a whip and a number of horses.The obelisk was designed by J. Bull, Inspector of Mail coaches. It is reassuring to know that he took his responsibilities seriously. He tells us that Colonel Gwynn of Glan Brian Park , Daniel Jones and a man called Edwards were sitting outside, up there with the driver. Didnt they notice that Jenkins was over-refreshed? Or were they passing the bottle around? Not wise really when you consider that one of the three inside passengers was a solicitor from Llandovery called David Lloyd Harris. A solicitor can be very touchy in certain circumstances, I find.Bull used the 13 pounds 16 shillings and sixpence he received from 41 subscribers to erect the obelisk in 1841. How very public spirited they were in those days. As an Inspector with both technical and human resource management responsibilities how he must have yearned for the breathalyser and the invention of traffic calming measures.But I think it was money well spent. It might not have been as hard hitting or as effective as recent road safety campaigns but it has survived a great deal longer.