The battle between independent publisher Quarto and rebel activist investor Harwood Capital escalated yesterday ahead of a crucial vote on 7 November.
Harwood – which is hoping to oust the publisher's founder and chief executive, Laurence Orbach – has written to the UK Listing Authority to complain that the publisher was late in sending a circular about the vote to shareholders.
The activist investor, which represents 19 per cent of the shares, wants a delay, saying Quarto's circular was "in breach" because it should have been sent 14 days in advance.
Harwood claims that Quarto has underperformed under Mr Orbach and has criticised it for making "indulgent" purchases such as The World of Fine Wines.
But Quarto hit back, saying the wine publication had won "yet another award" and "increased its profit and revenue".
Group sales tumbled 2.7 per cent to $127m (£79m) in the past nine months.
Those close to Quarto point out that the Listing Authority approved publication of the circular.