The share price, which has declined steadily since peaking at 45.5p last April, dipped a further 1.75p to a new year's low of 16.75p. When the company was known as Ratners, and headed by Gerald Ratner, the shares traded as high as 300p.
Mr O'Brien will leave at the end of next month to become chief operating office at the fast-expanding Salisburys Stores, the company bought out of Signet for £3.8m last August and headed by Stephen Hinchliffe. Since buying Salisburys, Mr Hinchliffe has been on a spending spree, picking up Sock Shop, Torq, and Red and Dead.
Walker Boyd, finance director of Signet's UK Jewellery business, who has been with the company for two years, has been promoted to the board and will succeed Mr O'Brien. Before joining Signet , he was finance director of Grattan, the mail order company, where he worked for three years.There is no heir-apparent to Mr Light. His responsibilities in the US are being assumed temporarily by Laurence Cooklin, chief executive of UK Jewellery.
Despite a return to profitability and prospects of a sustained recovery, Signet remains saddled with debt problems.