It's from a comedy sketch from the Mary Whitehouse Experience. Rob Newman and David Baddiel are contemplating valentines cards.
Newman: "Oh I love you with all my heart.... Yours sincerely.... Rob Newman."
Baddiel: "No. Too obvious. You have to make it more obscure."
Newman: "Oh I love you with all my heart... Yours... Nob Rewman."
Baddiel: "Still not good enough. But it's probably wise to avoid being too cryptic..."
Newman: "Oh I love you with all my heart.... Yours... Flange of baboons in mining country, perhaps? (3, 6)"
Ever since then it's been my standard 'impossible cryptic clue'. So there you go.
Whoa, did that timeframe and the word obscure bring some good odd memories back! Think Antigua, Guatemala in the Fall 1991 and me enjoying a couple of nice Cerveza Obscura's... 8)
(Cerveza obscura means a dark beer in Spanish, but the cool thing was that the local beer really was named 'Cerveza Obscura' and utterly black!)