Green’s Dictionary of Slang

lunatic soup n.

also lunatic’s broth

1. cheap alcohol; spec. cheap red wine.

DT 20 June ii I: He explained his action by saying that he was in lunatic’s broth – otherwise drunk – at the time [F&H].
[Aus]Baker Popular Dict. Aus. Sl. 45: Lunatic soup, cheap red wine.
[UK]M. Harrison Reported Safe Arrival 125: I must have a taste of decent liquor. Or even a bottle of Red Biddy. Lunatic’s Broth.
[Aus] ‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxvi 4/1: lunatic soup: Booze of any description.
[Ire]S. McAughtry Belfast 6: My job’s to keep the cutomers supplied with lunatic broth.
[Aus]R. Aven-Bray Ridgey-Didge Oz Jack Lang 15: His acting the purse man brought the place to life. The bots ordered up only the best brands of lunatic soup from the top shelf.
[Aus]R. Beckett Dinkum Aussie Dict. 35: Lunatic soup: Alcohol in any form.
[Aus]N. Cummins Adventures of the Honey Badger [ebook] I was pretty stoked and nervous, with all of my long-lost relations making the game, and half full of lunatic soup.

2. (also electric soup) methylated spirits as drunk by alcoholics.

[Ire]D. MacDonagh Happy as Larry Act IV: Was it brandy I drank on top of whiskey, / Or poteen brewed from Connachtmen’s socks, / Or Lunatic Soup or American hooch.
[Ire]S. McAughtry Belfast 146: The cops knew him as harmless: just too fond of the electric soup.
[NZ]McGill Dict. of Kiwi Sl. 70/2: lunatic soup alcoholic drink, including meths (methylated spirits).
[Ire](con. 1930s) M. Verdon Shawlies, Echo Boys, the Marsh and the Lanes 62: In those days some of the men went on benders. They’d go mad for the drink, absolutely mad [...] Some – not many – but some would even drink methylated spirits. They would. ‘Lunatic soup’, we called it.
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].