Advent International, the pan-European private equity firm, has dismissed reports that Luke Johnson, chairman of Belgo Group, the frites-et-moules bistro chain, was preparing a bid for Waterstones, the book chain owned by HMV Media, an Advent portfolio company.

Advent, which has around 43% of HMV Media alongside a similarly sized stake held by EMI Group, said the bid would not be completely implausable. But so far no approach had been made.