Shares in Yell, already down 80 per cent last year, have tumbled a further 70 per cent over the past three months reflecting increasing concerns about the directory publisher’s capital structure and ability to refinance.

Moody’s, the ratings agency, placed the stock under review for a possible downgrade last month citing concerns over the group’s ability to meet its senior credit facility covenants if it were to experience “high single-digit revenue declines” this year.