In British English, Ruby Murray, the name of a Northern-Irish singer (1935-1996), is rhyming slang for the noun curry, denoting a dish of meat, vegetables, etc., cooked in an Indian-style sauce of hot-tasting spices and typically served with rice.
These are, in chronological order, the earliest occurrences of Ruby Murray, rhyming slang for curry, that I have found:
1-: From an interview of the Cockney drummer Jeff Seopardie, published in The Standard (London, England) of Thursday 24th March 1983:
FOOD: I love yer actual meat and two veg but my favourite has to be a Ruby Murray (Curry).
2-: From the script, by John Sullivan (1946-2011), of Healthy Competition, episode 2, broadcast on Thursday 17th November 1983, of the 3rd series of the BBC television comedy Only Fools and Horses—as published in Only Fools and Horses: The Bible of Peckham (BBC Books, 1999):
Del: Well, I’m off out.
Rodney: Where you going?
Del: Well, I thought I might go down and have a couple of light ales down the Nag’s Head, and then go on to the Star of Bengal for a Ruby Murray. Coming?
3-: From Indian rising, by Drew Smith, published in The Guardian (London and Manchester, England) of Friday 4th May 1984:
There are many theories as to what has brought Indian restaurant food from the take-away “Ruby Murrays” used as blotting-paper when the pubs closed, through staidly plush provincial places, streamlined vegetarian cafes and tandoori houses to the present sophisticated “palaces.” On the one hand, travel and the media have educated people to distinguish between the various styles of cooking, and the new awareness of healthy eating patterns has brought many to an increasingly vegetarian diet. And on the other, ambitious and often youthful Indians have taken advantage of this new interest to open places—and make profits—which would have seemed incredible 10 years ago.
4-: From the Evening Post (Reading, Berkshire, England) of Thursday 12th February 1987:
Cockney TV actor Tony Selby was in Reading last night for the opening of a new-style Indian restaurant.
Curry fan Tony, of Get Some In, told guests at The Raj, in London Road: “I have always loved a Ruby Murray.”
5-: From Uneasy lies the head . . ., by Sue Arnold, published in the Observer (London, England) of Sunday 13th September 1987:
It is well known that with the exception of the Chinese tour, which was of particular historical significance, the Queen’s visits get comparatively scant Press coverage and this upsets her—‘It ain’t her fault,’ observed one of the pop reporters polishing off his Ruby Murray (curry), a diet he adheres to exclusively whether in Caen or Canada, ‘I just can’t get the old baked bean in the paper these days. It’s all Di and Fergie.’
6-: From an interview of Ruby Murray, by Tony Jones, published in The Journal (Newcastle upon Tyne, Northumberland, England) of Saturday 14th November 1987:
Her name lives on among a new generation who have never heard her sing. A ‘Ruby’ has become a legendary part of cockney rhyming slang (Ruby/Ruby Murray/Curry) and has since been adopted by a wider audience. That never fails to tickle Ruby, who has never been in danger of taking herself too seriously: “It started with the musicians, you know, when they were in rehearsal and had time to pop out for a ‘Quick Curry-Ruby Murray.’ They were the ones who came up with that one—and it stuck.
“I think it’s rather nice, don’t you? An Irish girl becoming a part of the cockney language!”
7-: From Time for an Indian summer, by James Walling, published in the Evening Chronicle (Newcastle upon Tyne, Northumberland, England) of Tuesday 12th September 1989:
There was a time when I simply did not like Indian food […].
Now, whilst not actually capable of going so far as to sell the family silver (OK—aluminium!) to buy a Ruby Murray (Ruby Murray—curry; geddit?), I wouldn’t like to put it to the test in an emergency.