The British- and Irish-English noun knacker’s yard designates:
– [in literal use] a place where old or injured animals, especially horses, that are unfit for human consumption, are killed and their bodies processed so the body parts can be used;
– [in transferred use] a notional place where ends up someone or something that is no longer useful or successful.

A transferred use of the noun knacker’s yard occurred, for example, in Putting the Lid on It, by K. R. G. Browne, published in the Scunthorpe Evening Telegraph (Scunthorpe, Lincolnshire, England) of Monday 31^st July 1939:

The problem of what to do with his hat, as a matter of fact, is one that confronts every man pretty often during his life, chiefly because he hates to be parted from it. The Englishman’s affection for his lid is a very beautiful thing, compared to which the love of a tigress for her young is just a thinly-veiled dislike; and he will suffer agonies of discomfort and contortion rather than let it get away from him.
And the older the hat, of course, the greater his unwillingness to let it out of his sight. Because they make him feel self-conscious, conspicuous and hot about the temples, the normal male buys new hats rarely and with reluctance, preferring to cherish his current model until it starts to fall apart. Only when daylight begins to show between the brim and the crown does he consign it sorrowfully to the knacker’s yard and stand his head another.

 

EARLIEST LITERAL USES OF KNACKER’S YARD

 

The first two occurrences of the noun knacker’s yard that I have found are as follows:

1-: From a letter on cruelty to animals, dated Tuesday 25^th November 1823, by John Lawrence (1753-1839), an early advocate of animal welfare and rights—letter published in The Monthly Magazine; Or, British Register (London, England) of March 1824:

The horrible principle, be it instinctive or customary, of deriving pleasure from deliberately contrived tortures,—riding horses to death in the field, and driving them to death upon the road,—the treatment of that most oppressed and tortured victim under heaven, the poor stage-horse, in the latter and excruciating part of his career; his progress thence to Smithfield, to the green and fish-cart, to those actual hells, the nacker’s [sic] and catgut-maker’s yards.

2-: From The Times (London, England) of Monday 7^th May 1827:

We speak the common sense of the country in affirming, that when the dust which these old cart horses of the Government have raised, by restiveness and prancing on a road which is strange to them, shall have subsided, it will be discovered that their numbers are but few, their paces feeble, their condition miserable, and the prices which they may again be bought at, little more than what are current in a knacker’s yard.

That knacker’s yard is a British-English noun is illustrated by the following paragraph from the New England Farmer, and Horticultural Register (Boston, Massachusetts, USA) of Wednesday 20^th December 1843:

It seems that in London there are certain establishments where horses are slaughtered, called knackers’ yards. The wretches who keep these places buy horses expressly for slaughter—selling their carcasses and hides.

 

EARLIEST TRANSFERRED USES OF KNACKER’S YARD

 

The first two transferred uses of the noun knacker’s yard that I have found are as follows:

1-: From The Atlas. A General Newspaper and Journal of Literature (London, England) of Sunday 29^th January 1832:

Mr. Hume’s notion of repealing the Superannuation Act is out of character with his liberality. But a man who is eternally making blows without aim with a hammer, must miss as often as he hits. We are not surprised Mr. Hume misses so often. He hits wide of his mark when he has one, and is at best but a random hand even when he hits the nail on the head by accident. The Superannuation Act is the last cushion (and a hard one it is) of the clerks in government offices. When they are worn out, after a servitude in which they spend their lives, earn little, and are rendered unfit for all other occupations, they are removed on a retiring allowance proportionate to the period of their service. Mr. Hume believes this to be a serious burthen to the country, and seems to think that government clerks should be sent to the knacker’s yard, when they cease to be capable of work.

2-: From A Letter to Francis Baring, Esq., Joint Secretary to the Treasury. By an Old Whipper-In, published in Fraser’s Magazine for Town and Country (London, England) of May 1835:

There devolves on you that unpleasant duty of holding a hand over the most miserable set of hacks ever consigned to a knacker’s yard.
I speak, my dear Frank, of the actual ministry—the doomed dozen. God pity you with them. Spring Rice may tell you of a plan in his own country of making plumpuddings without plums. It is realised in the present cabinet. Here we have the plumless plumpudding , viz. the mess of Melbourne, Lansdowne, Auckland, Holland, Duncannon, Jack Russell, Palmerston, Grant, Boghouse, Howick, Thomson, and Spring Rice. There they are, Frank Baring, there they are; and do you not from the bottom of your boot-heel pity and compassionate the set. I am sure you do, for you are a good-hearted youth, though stupid.