Morrisons has failed to stem the slide in sales at Safeway

In the 12 weeks to 23 May, Safeway's market share fell to 8%, down from 8.2% in the 12 weeks to 25 April.

Market research firm TNS added that sales at Safeway's stores were down 8% on the year.

However, Morrisons has managed to grow its market share to 6.2% from 5.7% a year earlier, helped by sales growth of 15% over the year.

Sell-off

When the �3bn deal went through in March, Morrisons pledged to overhaul the 427-strong Safeway estate over the next three years.

In May, it sold off 14 Safeway sites to Sainsbury's to comply with anti-monopoly conditions set out by the Competition Commission.

According to the figures from TNS there was little change among the top three names.

Tesco extended its lead over its rivals slightly, taking a 27.6% share of the market - compared with 26.5% the previous month - with sales up 10% on the year.

Wal-Mart owned Asda saw its market share unchanged from a month earlier at 16.6% and Sainsbury was also unchanged at 15.5%.