A significant character in the book is Walter Plinge, the Opera House's clumsy and not-too-bright odd-job man. He is, quite possibly, really the suave "Opera Ghost", but is described in terms remeniscent of Frank Spencer, the lead character of the BBCsitcomSome Mothers Do 'Ave 'Em. The joke is that this character was played by Michael Crawford, who went on to play the Phantom in the Andrew Lloyd-Webber musical.
The title is a pun on Masquerade, a key song in the musical.