The group started opening on Sundays last November because it feared its customers were being tempted to shop at rivals.
'At best, we have stopped the erosion,' said Martin Ackroyd, finance director. He does not believe the extra sales generated are enough to cover the cost of Sunday opening.
The sales increase, from pounds 746.5m to pounds 861.8m, pushed pre-tax profits for the six months to July up 24.1 per cent to pounds 47.4m.
Operating margins increased from 5.2 to 5.6 per cent, partly due to an improvement in the gross margin as suppliers were squeezed and the mix of products sold shifted to more profitable items.
Ken Morrison, chairman, said trading remained 'extremely competitive with ever-present pressure on profit margins'. Tesco recently cut prices in some stores in North-west England, Morrison's heartland.
Earnings per share rose 19.8 per cent to 4.05p and the interim dividend is increased by a similar proportion to 0.24p. The shares closed 1p lower at 138p.Reuse content