Just to throw another complication into the mix, I found some exemptions to dogs that can be shot.
- The above defence does not apply to all dogs: sheepdogs, police dogs, guide dogs, working gun dogs and pack hounds are all exempt and under no circumstances should be shot.
Sorry but you are cherry picking pargraphes from legislation here and quoting out of context.
The paragraph you quote above is from the Dogs (Protection of livestock) Act 1953. That Act makes no reference to the circumstance in which you can shoot a worrying dog. Tp put it into contect I have added further wording from this Act below.
1 Penalty where dog worries livestock on agricultural land.E+W
(1)Subject to the provisions of this section, if a dog worries livestock on any agricultural land, the owner of the dog, and, if it is in the charge of a person other than its owner, that person also, shall be guilty of an offence under this Act.
(2)For the purposes of this Act worrying livestock means—
(a)attacking livestock, or
(b)chasing livestock in such a way as may reasonably be expected to cause injury or suffering to the livestock or, in the case of females, abortion, or loss of or diminution in their produce.
or
(c)being at large (that is to say not on a lead or otherwise under close control) in a field or enclosure in which there are sheep
(2A)Subsection (2)(c) of this section shall not apply in relation to—
(a)a dog owned by, or in the charge of, the occupier of the field or enclosure or the owner of the sheep or a person authorised by either of those persons; or
(b)a police dog, a guide dog, trained sheep dog, a working gun dog or a pack of hounds.
So in the proper interpretation "a police dog, a guide dog, trained sheep dog, a working gun dog or a pack of hounds." only applies in relation to "being at large (that is to say not on a lead or otherwise under close control) in a field or enclosure in which there are sheep"
The legislation that does provide a defence for killing a worrying dog is the Animals Act 1971 and a quote below (note no mention of police dog, a guide dog, trained sheep dog, a working gun dog or a pack of hounds)
9 Killing of or injury to dogs worrying livestock.
(1)In any civil proceedings against a person (in this section referred to as the defendant) for killing or causing injury to a dog it shall be a defence to prove—
(a)that the defendant acted for the protection of any livestock and was a person entitled to act for the protection of that livestock; and
(b)that within forty-eight hours of the killing or injury notice thereof was given by the defendant to the officer in charge of a police station.
(2)For the purposes of this section a person is entitled to act for the protection of any livestock if, and only if—
(a)the livestock or the land on which it is belongs to him or to any person under whose express or implied authority he is acting; and
(b)the circumstances are not such that liability for killing or causing injury to the livestock would be excluded by section 5(4) of this Act.
(3)Subject to subsection (4) of this section, a person killing or causing injury to a dog shall be deemed for the purposes of this section to act for the protection of any livestock if, and only if, either—
(a)the dog is worrying or is about to worry the livestock and there are no other reasonable means of ending or preventing the worrying; or
(b)the dog has been worrying livestock, has not left the vicinity and is not under the control of any person and there are no practicable means of ascertaining to whom it belongs.
(4)For the purposes of this section the condition stated in either of the paragraphs of the preceding subsection shall be deemed to have been satisfied if the defendant believed that it was satisfied and had reasonable ground for that belief.
(5)For the purposes of this section—
(a)an animal belongs to any person if he owns it or has it in his possession; and
(b)land belongs to any person if he is the occupier thereof
While I am not a lawyer I have spent a considerable time researching this subject, as an agricultural advisor, and have written papers on teh subject that have been vetted by our lawyers