Supermarket giant Morrisons today announced a dramatic boardroom shake-up, a year on from its £3 billion acquisition of Safeway.

Finance director Martin Ackroyd announced he was quitting the company after 31 years while existing joint managing director Bob Stott has been named as the company's first ever chief executive.

Chairman Sir Ken Morrison also revealed that existing non-executive director David Jones is to become deputy chairman of the company. The company's other non-executive director, Duncan Davidson, said he was quitting his post with the firm less than a year after joining.

The changes were announced as the company unveiled a fall in pre-tax profits to £297.1 million, down from £319.9m last year, on sales of £13 billion. Operating profit was £321.1m, in line with the figure announced in last week's profit warning.

Sir Ken said he believed Morrisons now had "the right team to deliver the full benefits of the Safeway acquisition".

One of the key roles for Mr Jones, the Ilkley-based chairman of retail giant Next, will be to ensure good corporate governance is practised within the company and to identify new non-executive directors as well as successors for all the company's board positions.

However, the 72-year-old chairman insisted that he still had no plans to stand down. "I might start to have weekends off," he quipped.

The string of changes came as the company was facing increasing pressure from investors in the wake of two profit warnings within the space of a year. Mr Ackroyd had been facing calls for his resignation since the company announced last week that a review of sums owed to Safeway would cause a £40 million provision in the annual results.

Mr Ackroyd will remain on the board until the Annual General Meeting in May when a successor will be named. Sir Ken said today he hoped it would be a matter of weeks before new non-executive directors are announced.

Meanwhile, Morrisons said it was pleased with the performance of the former Safeway stores. The average customer spend per basket was £21, just below the Morrisons basket price of £25, while performance had been better at stores in the north than in the south.

Like-for-like sales at the existing Morrisons stores were up 2.7 per cent, but the Safeway outlets yet to be converted saw a fall of 6.8 per cent.

Sir Ken admitted to the Telegraph & Argus that today's boardroom shake-up was "a little bit different to the way we normally do things" but insisted that the company was laying the foundations for future challenges rather than reacting to pressure from analysts.

Chief executive Mr Stott said the company had always expected the acquisition of Safeway to cause financial challenges and had always been about acquiring more properties.