Originally and chiefly British English, the phrase after the Lord Mayor’s Show (comes the, or a, dung-cart, or muck-cart, etc. ¹) designates an anticlimactic or disappointing end following an otherwise exciting, impressive or entertaining display.

¹ In fact, any word can be the subject of the verb come in after the Lord Mayor’s Show comes—as explained by George Waters at the end of the description of a procession of the Nawab of Sucheen and his retinue—description published in Indian Gleanings and Thoughts of the Past (Chatham: G. H. Windeyer, 1864):

Several Arab horsemen, armed cap-a-pie, galloped to and fro, and, as is usual on all such occasions, after gaiety comes squalor; or, as we observe in respect to the annual pageant of the City of London that “after the Lord Mayor’s Show comes a—donkey-cart,” or anything your imagination may dictate, so, in this instance, the rear of glittering ostentation and finery was brought up by a decrepit old nigger driving a miserable bullock-gharry, the animals in which appeared so proud of their bones, that they were exposing them, much to the inconvenience of a tight skin.

—Cf. also, below, variations on the phrase.

The phrase after the Lord Mayor’s Show (comes the, or a, dung-cart, or muck-cart, etc.) refers to the cleaning-up, especially of horse-dung, necessary after the Lord Mayor’s Show, a ceremonial parade and pageant held annually in the City of London on Lord Mayor’s Day—i.e., the day on which the new Lord Mayor of the City of London goes in ceremonial procession to the Royal Courts of Justice (formerly to Westminster), to be presented to the Lord Chief Justice and to swear allegiance to the monarch. Lord Mayor’s Day dates back to 1215; it used to be the 9^th of November, but since 1959 it has always been the second Saturday in November.

 

The Lord Mayor’s Show of 1958—photograph from The Sphere (London, England) of Saturday 15^th November 1958:

 

The earliest occurrence of the phrase that I have found is from Trewman’s Exeter Flying Post (Exeter, Devon, England) of Thursday 21^st August 1851:

Throwing a Sprat to Catch a Mackerel.—The Torquay band has been reorganised, and the members are astonishing the natives during evening hours with their efforts. We are afraid to say how many times these “harmonious” gentlemen have been divided by the petty jealousies which are continually springing up among them, and which prevents their obtaining any degree of proficiency in their attempts, but it is very certain that they are scarcely heard from one end of the year to the other, except a few weeks before the regatta, when the hope of an engagement draws them together for a short time. Surely their credit ought to act as a cement, and infuse a spirit of rivalry with other towns among them, when they hear to what perfection the bands of Teignmouth and other places have arrived by application and friendly feeling. If the amateurs of Torquay carry out the same principle there will be found no lack of talent among them, and other bands will not usurp their place and profits. At present the performances of the Teignmouth and Torquay bands remind us forcibly of the observation on vulgar parlance “After the Lord Mayor’s show comes a dung cart.” And until the musical aspirants of this town show themselves deserving of a better simile, we hope our townsmen will not encourage such petty and disgraceful squabbles, which only serve to confine their musical aspirations to a scale in point of pecfection [sic] many degrees lower than a chorus of pigs, which to say the worst of it is natural.

The second-earliest occurrence of the phrase that I have found is from the account of a meeting of the Beverley Town Council, in Yorkshire, published in The York Herald, and General Advertiser (York, Yorkshire, England) of Saturday 14^th October 1854:

Mr. Boyes said it was much to be regretted that the old London saying “after a Lord Mayor’s show comes a dust cart,” was about to be realised. It was very unfortunate that the agreeable business in which they had been engaged of expressing their loyalty to her Majesty, should be followed and ahoyed [?] by the disgraceful consummation of a compact or agreement entered into some time ago by several members of the Council. A bargain and sale had been made. So much apostacy for so much vanity. An understanding, conceived in prejudice and carried on by corruption and ingratitude, had been entered into, and the climax of all was put on at the last meeting by a succession of unmitigated falsehoods.

According to The Beverley Recorder, and General Advertiser (Beverley, Yorkshire, England) of Saturday 13^th November 1858, the same person, Mr. Boyes, used the phrase again during the election of a new Mayor:

Mr. Boyes concluded by stating that he would not disguise his feelings, or restrain the utterance of his opinion, that Mr. Robinson was the most unfit person to be Mayor of any he had ever known during the twenty-one years he had been in the Council. (Applause) The retiring and the incoming Mayor reminded him of the old saying, “after the Lord Mayor’s Show comes a dust cart.” (Laughter and cheers)

 

VARIATIONS ON THE PHRASE

 

Some of the numerous variations on the phrase are particularly interesting:

1-: From a letter about the education system in Ontario, by a person signing themself ‘Truth’, published in The Toronto Daily Mail (Toronto, Ontario) of Saturday 27^th November 1886:

The older men who remember the times of Ryerson ² look about them and are occasionally startled at the change. After the Lord Mayor’s show comes Mr. Ross ³; after the wise and venerable uprightness of a Chief whose opponents respected his character and attainments, comes the limp and contemptible truckling of a politician whose foes deride and whose friends pity him.

² Egerton Ryerson (1803–1882) was a Canadian provincial educator and Methodist church leader who founded the public education system of what is now Ontario province.
³ George William Ross (1841-1914) was Ontario’s Minister of Education from 1883 to 1899.

2-: From Cricket Notes, published in The Western Times (Exeter, Devon, England) of Tuesday 2^nd August 1887:

The first of the Wandering teams have visited Devonshire and so far have done remarkably well: the Crofton Wanderers who hail from Yorkshire, and include some manly specimens of that Northern shire, inflicted a signal defeat on the Exeter men at Grâslawn, last week, the bowling and batting of S. Hayley being the principle cause of the downfall, and after the Lord Mayor’s show on Saturday against Newton Blues, the proverbial dung cart was very conspicuous.

3-: From The Sporting Life (London, England) of Saturday 27^th September 1890:

Plumpton ⁴ September Steeple Chases.—After the Lord Mayor’s show comes an omnibus, and the descent from Newmarket ⁵ to Plumpton is almost as abrupt.

⁴ Plumpton is a village in East Sussex, a county of southeastern England.
⁵ Newmarket, a town in Suffolk, a county of eastern England, is a noted horse-racing centre.

 

SHORTER FORM OF THE PHRASE

 

The earliest occurrence of the shorter form after the Lord Mayor’s Show that I have found is from the Turf section of the Sunderland Daily Echo and Shipping Gazette (Sunderland, County Durham, England) of Wednesday 6^th July 1904:

It was a case of “after the Lord Mayor’s Show,” as the old saying has it, with Higgs at Nottingham yesterday, for after steering Itinerary to victory he finished last of all in the next race.

Tom O’Lincoln used the shorter form of the phrase in the account of a soccer match between Lincoln City and Stockport, published in The Lincolnshire Chronicle and General Advertiser (Lincoln, Lincolnshire, England) of Monday 26^th September 1910:

Lincoln’s Weakness.
[…] I am afraid I cannot say a great deal in favour of Yule, Robertson and Reid, the three inside forwards. In the case of Yule, it seemed to be something in the nature of “After the Lord Mayor’s show.” After his conspicuous brilliance against Leeds City he descended to something which was quite mediocre.