The association said that in 2010 sales of e-books and audio book downloads in the "general titles" category, which includes novels and consumer titles, shot up from £4m to £16m.

Academic and professional books still dominated overall digital sales, which reached £180m last year.

It still remains a small proportion of total book sales, which hit £3.1bn.

However, the increased digital sales suggests devices such as Amazon's Kindle and the Sony Reader are increasingly making an impact.