Independent stores are teaming up with larger groups

Independent store numbers fell by 7% in the last year while sales fell 5%, IDG found. The UK convenience store sector is worth �23.9bn.

In contrast, sales at convenience store formats owned by supermarkets - such as Tesco Metro - shot up by 18%.

Despite the fall, independents still account for half of all corner shops.

Buying power

The report also said that a growing number of independent stores had either closed or affiliated themselves with specialist convenience store operators such as Spar or Costcutter.

Such alliances allow them to improve their buying power and increase spending on marketing.

Sainsbury's and Tesco are both targeting the convenience sector as an area they want to grow Rhys Williams, Seymour Pierce

These stores - known in the industry as 'symbols' - now account for 23% of all store numbers and almost a third of convenience sector sales.

"Some of them are doing very well on their own," an IGD spokeswoman told the Press Association.

"'Symbols' can give them some of the support and advice that they don't have so they can draw on the knowledge of these established groups."

Big brands

Retail experts said the rising closure rate of independent stores was no surprise given the intense competition in the market.

The leading supermarkets have been developing their mini-store formats at a rapid pace in the past few years, led by Tesco and Sainsbury's who have been buying up smaller sites.

Tesco and other supermarkets are eating into the convenience market

"Sainsbury's and Tesco are both targeting the convenience sector as an area they want to grow," said Rhys Williams, an analyst with stockbrokers Seymour Pierce.

"It means that independent stores trading against them can't compete and then they close."