Troubled retailer Sports Direct has blamed a massive slump in profits on the worst summer on record and a drop in consumer spending.

However, Mike Ashley, the controversial billionaire founder of the discount sporting goods chain, said he had no plans to take the company private as he unveiled a 73% drop in pre-tax profits in the first half of the year.

There have been three profits warnings since the company was taken public in February and the share price has dropped more than 70% since the initial public offering.

Sports Direct's chief executive, Dave Forsey, said the first half was the most difficult in the company's history.

He added that the England football team's failure to qualify for next year's European championships would cost the company £50m. Umbro, the team's official kit maker, has cut production of the new replica away shirt from 3m shirts to 1m, and Sports Direct also expects to sell much fewer home shirts, socks and England flags.

Analysts have repeatedly complained about lack of information and access from Sports Direct.

Mike Dennis, a senior retail analyst at Piper Jaffray, who rates Sports Direct as a hold, said it was a high-risk investment.

"A significant amount of investment is needed in this business. There is no sign that management have done anything to improve the stores, product quality or sourcing."

Ashley was characteristically unrepentant today, describing the fall in the company's share price as "pathetic" and blaming the City for over-reacting.

He also told analysts that he could "personally guarantee" that the England football team would qualify for the 2010 World Cup.

"There will be a frenzy. And I mean a frenzy. You watch the nation," Ashley said.

Sports Direct failed to name a new chairman today, saying it was continuing its search. The company has been without a non-executive chairman since May, when the previous chairman, David Richardson resigned following differences with the board.

Earlier this week it emerged that Ashley had planned to take the top job, installing veteran leisure industry executive Alan Jackson as his deputy. However, Ashley's plans were thwarted when Jackson ruled himself out.

Despite the drop in profits, shares in the company soared by nearly 20% today to 101p. Analysts said investors were comforted by Ashley's prediction that full-year profits could beat market expectations.