Marks and Spencer blamed the hot summer and lower levels of promotional activity for a 2.7% fall in second quarter food sales.

For the six months ended September 27, M&S posted a 7.4% rise in group pre-tax profit of £311.5m on turnover that moved 3% ahead to £3.8bn from £3.7bn last year.

Food sales were up 6.9% over the half year, but had dropped back from 8.1% in the first quarter to 5.4% in the second.

Chief executive Roger Holmes said that promotional activity on food for the autumn would be back to “normal levels”.

M&S said it has continued to extend its food offer by opening 20 stores in the first half, of which 19 were its Simply Food format. A further 35 stores are set to open by the end of the year, with some 500 sq ft of new food space - 150 stores - on plan for March 2006.

M&S chairman Luc Vandevelde was confident of progress as the group moves into the important Christmas trading period. He noted that it had grown market share in food, achieved efficiency gains and controlled costs to support investment in new initiatives.