It isn't every No.1 album which can lose almost 76% of its sales week on week and still retain a lead over the rest of the market, but then Lady Gaga's Chromatica is no ordinary chart-topper. Trailing for much of the week, the incumbent reasserted its dominance but still only tops the charts by the narrowest of squeaks, its chart sale of 12,819 a mere 571 copies ahead of its closest rival.

Gaga herself has taken extensive steps to play ...