Sometimes a particular name, word – or, in this case, number – can have an instant association, and that was certainly the case with this morning’s clue to the song that was Stuck in a Moment*. In fact 221b would’ve been enough of a giveaway without the clip it accompanied:
*Stuck in a Moment was Baker Street, from Gerry Rafferty’s album City to City, the giveaway clue of course referring to the address of Sherlock Holmes!