As, apparently, has the charity itself. "Anything that he does in his private capacity is beyond the sphere of our relationship with him," said a spokesman, Javier Arreaza, from the headquarters in Switzerland yesterday.
Anything? "His relationship with us has been very good for conservation. We cannot really begin to hypothesise."
Not that much hypothesis is necessary. Shooting is a long-established favourite pastime of the Royal Family and Prince Philip's total "bag" over the past 30 years stretches over continents, species and runs into mind-boggling numbers.
Figures compiled from press reports by the anti-bloodsports lobby suggest that in Britain alone he has shot deer, rabbit, hare, wild duck, snipe, woodcock, teal, pigeon and partridge, and pheasant numbering at least 30,000.
Prince Philip especially enjoys shooting wild boar on the estates of friends in Germany. On one occasion he and Prince Charles are said to have killed 50 wild boar in a single day.
He frequently invites sporting friends to the Royal Family's 20,000-acre Norfolk estate at Sandringham. In 1993, out shooting for up to four days a week during his seven-week stay, he hit his target of 10,000 pheasant. His shooting parties are estimated to have killed about 150,000 pheasant over the last two decades.
The Duke rarely listens to criticisms of his passion for shooting. In 1961, despite protests from British and Indian politicians, he went ahead with an Indian tiger shoot. On that trip he also killed a crocodile and six urials - a type of mountain sheep.
Although he has bowed to pressure and given up big-game hunting, Prince Philip continues to defend his love of blood sports and has frequently claimed that he is culling and not killing the animals.
But while the Royal Family is prepared to consider change in many areas, its enthusiasm for blood sports remains as much a part of royal life as corgis, speeches and divorce.
The Queen often accompanies the Duke on pheasant shoots. Prince Charles and the Princess Royal have organised competitions in which they lead rival shooting parties.
And it seems the royal passion will not dim with a new generation. Prince William is said to prefer shooting to any other sport, while Prince Andrew took his daughter Beatrice on a shoot when she was six.
In October, the Duke provoked an outcry by declaring shooting "an intelligent leisure activity" for children. He was backing a new book teaching novices about gun handling.