http://www.bbc.co.uk/news/uk-england-nottinghamshire-11751079
Basically, two walkers decided it was a good idea to walk in a field with a bull as the sun's going down. One gets killed, the other gets seriously injured. The bull is now due to be put down as a token gesture.
Now this begs the question, what's the point? It's tragic that somebody died, but putting the animal down is over the top. Bulls are highly territorial and aggressive animals, and you are considered incredibly lucky if you can enter a field with one and not expect any overt gestures of aggression.
It's completely different to putting down, say dogs for example, because they have to be maintained and cared for by people around the clock, who could be exposed to further vicious attacks. Bulls on the other hand are left to their own devices in fields all day long with minimal human interaction, and are dealt with in a professional and coordinated way that has plenty of contingencies in place to deal with aggressive livestock.
Why not just place the bull back where it was and just leave it in the agricultural process it was involved in? It was completely unnecessary to put it down in my opinion.