Supermarket Morrisons was under further pressure today after industry figures showed it lost ground to bigger rivals Asda and Sainsbury's.
Britain's fourth biggest grocer's market share dropped to 11.5% in the 12 weeks to September 2, from 11.7% a year earlier following the slowest growth of the 'big four' chains over the period, according to Kantar Worldpanel.
In a spell covering the Olympics and Paralympics, Asda and Sainsbury's posted market-beating sales growth of 4.5% and 3.8% respectively.
The latter's market share rose to 16.4% from 16.3% a year earlier, while Asda's lifted to 17.6% from 17.4% when excluding its Netto acquisition.
There was also evidence of a fightback by sector leader Tesco as its fall in market share eased back with a 30.8% share.
But Kantar said the big winners were outside the "big four", with successes at the two opposite ends of the industry as Waitrose and discounter Aldi held on to record share and growth.
Waitrose, which is owned by the John Lewis Partnership, grew its market share to 4.6% from 4.4% thanks to growth of 7.8% - outperforming the market average of 3.3% growth.
Aldi saw its market share leap to 2.9% from 2.4% a year earlier, having notched up growth of 26.6%.
Edward Garner, director at Kantar Worldpanel, said Aldi's growth was driven by "dramatic growth in spend levels of existing customers - up 36% over the past two years - rather than an increased number of shoppers".
He added that the slide in market share at Morrisons was "inevitable" as it currently offers no online shopping service and has a limited number of convenience stores.
In half-year results last week, reported profits from Morrisons fell £9 million to £440 million after underlying sales dropped 0.9% in the six months to July 29.
But the group is hoping to turn its fortunes around with plans for an online offering and by focusing expansion on new convenience stores in the south of England - where it is currently under represented.