The World Cup might still be six weeks away, but Asda and Tesco have started luring drinkers into store early with a "kamikaze" price war on beer.

On Monday, Tesco introduced a £10 deal on 24-packs of Boddingtons Draught, Foster's, Stella, Stella 4%, Strongbow, Corona and a 20-pack of Budweiser bottles.

Asda responded on Tuesday with a £9 deal on multipacks of Stella, Budweiser, Carlsberg Export, Boddingtons and Carling. "The days when supermarkets felt they could take advantage of consumers by putting prices up the week before Christmas or during the World Cup, are over," said Rick Bendel, chief marketing officer at Asda.

However, suppliers blasted the deep discounting as "madness" and declared the deals as further evidence that retailers viewed beer as a loss leader.

The sales director of one lager company calculated that after stripping out duty and VAT, the £9 deals would result in some suppliers losing up to £6 per case. "I've been in the beer industry for 37 years and cannot remember such ruthless, kamikaze trading. This is probably leading to two-cases-for-£16 deal as the World Cup gets nearer," he said.

With premium brands including Stella 4% and Budweiser among the deals, AB InBev was highlighted as being "at the forefront of the deals" by an insider. AB InBev UK president Stuart MacFarlane claimed he wasn't surprised as Stella was the biggest alcohol brand in the off-trade [Nielsen] and Budweiser was the official beer sponsor of the World Cup.