Greg F really does not know what he is talking about. Problem with using rifles to kill foxes is that in the UK the restrictions on using firearms means that the opportunities to take a safe shot are rare:

1 - must be a certain distance from a road or any form of human habitation.

2 - cannot fire towards or across a road, public right of way or any building.

3 - there must be a confirmed hard stop (i.e. a hill or banking) behind the target.

4 - the target (a fox in this case) must present a clean kill shot to the marksman which basically means that the fox has to be side on to the marksman.