As well as rules to which pilots must adhere at air shows, in the UK we have requirements for pilot qualification and recency, and we police the displays very thoroughly via flying control committees. Rules in themselves are not enough. Therefore, let us look at this tragic accident over a wider perspective than just a set of rules.
So saying, in the UK military and civilian pilots operate to different sets of rules; the display rules for military pilots are laid out in JSP 318 - Military Flying Regulations, and for civilian pilots in CAP 403 - Flying Displays and Special Events: A Guide to Safety and Administrative Arrangements. In addition, many air shows impose more stringent restrictions than those stipulated in the aforementioned documents. We have, sadly, had some accidents at UK air shows in recent years and, although there have been injuries and fatalities involving the aircraft crews, there have been no injuries or fatalities to the crowd when operating to the current rules. Please let there not be a kneejerk reaction to this appalling event.
There will obviously be much speculation as to why this aircraft crashed. One point of interest to observe when watching the video footage is that there were vortices visible over the upper surface of the wing for much of the pullout but then they disappeared just before the left bank was established immediately prior to impact.
My deepest condolences to the families of the deceased and to those injured.