UK dopers: origin of "No sex please, we're _____ " phrase

[Hail_Ants]

I’ve heard this in various Britcoms forever. Its even in the original HHGTTG radio plays. So what is it from and what does/did it mean?

[Cunctator]

There was the 1973 film. I don’t know whether there are earlier references.

[commasense]

From here:

Although No Sex Please, We’re British is best known as the phenomenally successful stage comedy which ran in London’s West End from 1971 to 1987 (it remains the longest-running comedy ever, with 6,761 performances to its name), it was also adapted into an equally farcical movie, starring Ronnie Corbett (replacing Michael Crawford, who had featured in the original stage version), Arthur Lowe and Beryl Reid.

One gets the sense that the title might hearken back to some other phrase, perhaps common among traveling Britons, No xxxx please, we’re British. If that’s what the OP is getting at, rather than the play I have cited, I have nothing. But I’d like to know, too.