Green’s Dictionary of Slang

the longest possible odds, an absolute certainty.

1752		Murphy Gray’s Inn Journal No. xi: 30 Dec. I’ll lay all Lombard-street to an egg-shell that it is true.
1799		Sporting Mag. Mar. XIII 337/2: I’ll hold you one hundred pounds to a China orange, that your Magazine is neglected as low and vulgar.
1819		‘One of the Fancy’ Tom Crib’s Memorial to Congress 38: All Lombard-street to nine-pence on it. *Note. More usually Lombard St. to a china orange. There are several of these fanciful forms of betting – Chelsea College to a sentry-box; Pompey’s pillar to a stick of sealing-wax, etc. etc.
1821		‘An Amateur’ Real Life in London I 83: There was a most excellent mill at Moulsey Hurst on Thursday last, between the Gas-light man, who appears to be a game chicken, and a prime hammerer — he can give and take with any man — and Oliver — Gas beat him hollow, it was all Lombard-street to a china orange.
1823		Morn. Post (London) 27 Mar. 3/4: It was no Lombard-street to an orange.
1825		‘Lighterman’ in Universal Songster I 23/2: ‘A China orange to Lombard Street / on Jack,’ the boys did cry.
1826		G. Daniel Sworn at Highgate I iv: I’d bet Lombard Street to a Brummagem sixpence.
1832		Egan Bk of Sports 52: He must prove the winner, ‘Lombard Street to a China-orange’ and no mistake.
1840		Hertford Mercury 19 Dec. 2/6: We would bet Lombard Street to a China orange that he never gets in.
1849		Lytton Caxtons I Pt iv 167: ‘It’s Lombard Street to a China orange,’ quoth uncle Jack. ‘Are the odds in favour of fame against failure so great?’ [...] answered my father.
1852		Exeter & Plymouth Gaz. 17 July 8/5: To draw any comparision between these men would be ridiculous [...] it was all Lombard Street to a China orange.
1853		Hereford Jrnl 7 Dec. 4/1: All Lonbard-street to an egg-shell, I have it! He’s staying with the Man in the Moon! [...] to a certainty!
1860		R. Nicholson Rogue’s Progress (1966) 102: Then the betting on Owen became St. Paul’s to a China orange.
1861		D. Cook Paul Foster’s Daughter III 241: What chance have I of winning Sylvia Foster now? [...] Why, it’s Lombard-street to a China orange against me!
1874		‘Old Calabar’ Won in a Canter I 27: ‘Now, Rasper, as you know, cannot ride, and my friend can, so it is Lombard Street to a China orange’.
1877		H. Hartigan Stray Leaves (1st ser.) 239: But ‘all Lombard Street to a China orange,’ there are few of my readers who have come across a description of a Christmas Day in a barrack-room.
1881		Morpeth Herald 1 Oct. 6/3: It’s Lombard Street to a China orange that I shall clap the darbies on him before morning.
1892		Eve. Standard 9 Nov. 1/1: We describe the betting upon a moral certainty as being all Lombard-street to a china orange.
1898		in N&Q CLII (1927) 189/2: Lombard Street to a china orange did not represent the odds against Horsford.
1903		N.Y. Dly Tribune 26 June 7/4: It’s all Lombard Street to a china orange against his bothering you [...] with any plea but guilty.
1908		Eve. Teleg. 24 Nov. 5/5: On Saturday it certainly looked all Lombard Street to a China orange on Preston North End.
1918		F. Muirhead Blue Guide to London 375: Lombard Street, the proverbial wealth of which is indicated in the phrase ‘All . . . China orange.’.
1921		A. Dobson Later Essays i ii: The eighteenth century ‘All ... China orange.’.
1928		Dundee Courier 22 Oct. 7/7: It seemed ‘all Lombard Street to a China orange’ on the ‘Vixen’.
1938		Eve. Teleg. 23 July 8/2: The betting is ‘all Lombard Street to a China orange’ that every one of the twelve will be [...] an advocate.