The government must open an inquiry into the supermarket giants’ monopoly of the retail market, a business pressure group has urged.

The call from the Forum of Private Businesses (FPB) comes as Tesco announces the launch of its first non-food store in Manchester this month, which the group said will “imperil” independent clothing, DIY, home furnishing and electrical shops.

“The supermarkets - and in particular, Tesco’s - dominance of retail trade is a catastrophe for the high street right here and right now in virtually every town in Britain,” said Nick Goulding, chief executive of the FPB.

“Supermarkets are spending millions on advertising and marketing creating this myth that they provide the best cost, quality and choice for the consumer. It will be exactly the same with the Tesco Homeplus stores.

“High street shops are powerless to compete with the aggressive anti-competitive tactics of supermarkets such as loss leaders which are deployed simply to kill off competition.”

Goulding called for a Competition Commission inquiry to protect the livelihood of small, high street shops but said it must go further than the last investigation in 2000, which left small, private firms in the cold.

“Another inert, toothless whitewash cannot and must not be accepted,” he said.

Tesco currently boasts a 30.5% share of the UK’s grocery market, which could increase to 45% if the firm advances its cache of 185 development sites.