According to various websites safety concerns about headstone stability were heightened during the 1990s by some 10 significant incidents known to HSE. Most involved children and 3 of them were fatal. Therefore, Bob S’s suggestion that the whole monument safety business/bandwagon arose from “one child being injured” is surely incorrect.
Though I’ve had minimal involvement myself with headstone safety, it seems that burial authorities, mostly local councils, were pushed by one or more strong letters from HSE during the 1990s into devoting considerable resources to checking and testing for unstable memorials and then taking action where it was thought necessary. In the past it was apparently the norm for standard type tall headstones to be attached to their sunken base stones by ferrous metal rods/dowels inserted into matching holes in the both stones. If moisture could reach such rods, they would be prone to gradual weakening through corrosion. Nowadays, this problem is avoided by the use of stainless steel or non-ferrous rods. Furthermore, it seems that from the 1960s, many burial authorities imposed a height limit for all new headstones, i.e. half or less than the height of the former standard type headstone. It’s likely that this trend was prompted by experience of accidents to people working with or near headstones and also visitors - all before the 1974 Act and HSE’s inception. In addition it’s quite likely that monumental masons wanted to reduce their costs by buying smaller-sized stones which also gave advantages regarding manual handling and storage at their premises. Please can anyone with better knowledge expand on these aspects?
Though the matter of headstone stability is very sensitive and controversial, I suspect that burial authorities have tended to concentrate on ensuring headstone stability in order to reduce their vulnerability to enforcement by HSE, adverse media publicity and compensation claims, etc. arising from incidents involving headstones. By contrast, perhaps the risk of upsetting grave owners and visitors was regarded by some authorities as a lesser and cheaper option. Though grave owners are legally responsible for keeping headstones in a safe condition, burial authorities end up with responsibility in most cases because they have no way of identifying the grave owners, if any exist, for various reasons. For example, when people change address, how many bother to notify a burial authority when they ought to do so?
From visits to various cemeteries and graveyards in recent years (mainly in connection with urban geology and genealogy) I’ve noticed that some headstone stability measures evidently taken by burial authorities, or more likely their contractors, seem very crass, e.g. use of fencing posts hammered into the ground adjacent to headstones, large laminated warning notices and lots of coloured warning tape, and guaranteed to cause distress. However, in cases of old graves with tall headstones for which grave owners cannot be readily identified and contacted, is it really distressing or inappropriate for such headstones to be laid flat? For example, last year I managed to track down the grave of a great grandparent in a large old cemetery. Though the headstone was lying flat (either intentionally or having been pushed over by vandals) I didn’t mind - in fact I was delighted that the side with the lettering on it was facing upwards and gave me ample new genealogical information. However, this was just my own reaction and I fully appreciate that others may feel very different about headstones being laid flat.