I should cocoa

[heretic666]

Reused by Supergrass as an album title; I think it was common usage in the RAF in WWII and means NO WAY. Any ideas as to derivation?

[Zhukov]

http://www.urbandicti...erm=I%20should%20coco

[Davethedog]

Longman's English Idioms adds a word of caution: 'This phrase is not recommended for use by the foreign student.'
But why 'cocoa'? As always when in difficulty with a phrase origin, turn to rhyming slang. 'Cocoa' is from 'coffee and cocoa', almost rhyming slang for 'I should say/think so!' Often used ironically. Current by 1936.
Dictionary of Popular Phrases (1990) by Nigel Rees

Nicked from Yahoo

[ojread2]

I still use it sometimes

[HowardKennitby]

Cassell's Dict of Slang agrees with DavetheDog

derivation from rhyming slang - cocoa = say so. Current from 1930s onward.

[heretic666]

Logical but wrong. I shoud cocoa is a polite way of saying F**k Off to an unreasonable request or suggestion.

[Zhukov]

How delicately put,heretic!...he was such a sweet boy! ;-)

[Davethedog]

So you ask a question recive not one but two replies that confirm the etymology of the phrase but, without offering your own soloution, dismiss it.

[heretic666]

I am new here and dont want to give the wrong impression

[heretic666]

Two identical answers do not preclude the possibility of error. I trust the OED otherwise my name speaks for me.

[HowardKennitby]

from OED

In phr. I should cocoa (Rhyming slang), I should say so. Freq. used ironically.

1936 J. Curtis Gilt Kid ii. 23 She don't do so bad, I should cocoa.
1964 Listener 31 Dec. 1053/2 _I should cocoa!' I retorts._ _They won't get me in the Kate---not in a million years they won't.'
1965 J. Porter Dover Three xi. 133 _She says you paid her a pound a week for the best part of nine months,' Dover went on. Mrs. Gomersall laughed scornfully. _I should co-co!' she chortled.
1967 O. Norton Now Lying Dead ii. 22 What me?_ I should coco. Sheila'd think I was off my head.

[heretic666]

Obviously I am not satisfied.............ever. Perhaps I should explain the context in which I was used to hearing it.
Q. Would you do the impossible/unreasonable?
A I should f*****g cocoa!
I had imagined it might date back to the early days of radio communications in aircraft. When given instructions or orders over a craclky radio 'Roger and Wilco' stood for right and will cooperate.
Back on terra firma the opposite to Wilco??????????Try A

[Quizmonster]

Click http://www.worldwidewords.org/qa/qa-ish1.htm for the view of an expert etymologist and lexicographer. (It's more just rhyme than rhyming slang, as NORMALLY construed...ie cocoa rhymes with say so, whereas, in general rhyming slang, the rhyme-word actually disappears.)

[chelle7272]

I grew up with my mother using the phrase and still say it myself sometimes. I can't see how you say it is a polite alternative to f off.
Other answers are correct imo, I've always used to mean 'I should say so'.