Leading supermarket group Tesco has seen its share of the UK grocery market drop to a seven-year low of 29.7 per cent this month, according to new research published today.

Data from Kantar Worldpanel shows that May 2005 was the last time that Tesco‘s market share was as low as it is currently, with trading continuing to prove difficult for the retail giant following a disappointing 2.3 per cent drop in like-for-like sales it posted for the recent Christmas trading period.

The overall grocery market grew 4.5 per cent during the 12 weeks to February 19th 2012, today‘s report reveals, which is broadly in line with the sector‘s performance over the past six months.

Worryingly for Tesco, although over market growth is still below Kantar‘s measure of grocery price inflation, many of its rivals are seeing their slice of the market hit all-time highs.

While consumer spending remains squeezed, many other grocers have managed growth in recent months, with Asda consolidating its position as the second biggest supermarket chain with 17.5 per cent of the market and upmarket rival Waitrose reporting a record share in this latest report.

Edward Garner, Director at Kantar Worldpanel, said: “While the growth rate remains lower than grocery price inflation, currently at 5.5 per cent, the gap between the two measures is narrowing – meaning pressure on household budgets, while still strong, is not getting any worse.

“The completion of its Netto conversions helped Asda retain its record share of 17.5 per cent that we reported last month. Waitrose saw its share rise this month to 4.5 per cent – an all-time record for the retailer.

“Its continuing strong performance shows that it is a mistake to talk about the ‘average‘ UK shopper. Some consumers clearly value good service and in-store experience when shopping, which Waitrose claims to provide.”

Waitrose has also experienced a climb in share due to an aggressive store expansion. The other major grocers have also been expanding but to varying degrees of success; while Sainsbury‘s upped their market share to 16.6 per cent in the period, Morrisons saw its fall from 12.3 per cent to 12.2 per cent.

At the value end of the market Aldi, Lidl and Iceland all saw double-digit growth in till sales during the period, with rises of 23.5 per cent, 10.5 per cent and 10.9 per cent respectively, to help them all hold on to record share of the market.