David Whelan, the founder of JJB Sports, promised in January that he would not sell his 29% stake in the retailer for 12 months.

Mr Whelan, chairman of Wigan Athletic, sold his 29% stake to Icelandic group Exista and Chris Ronnie on Friday.

In a statement to the London Stock Exchange on 26 January, he undertook "to not make further disposals of his shares for at least 12 months".

The statement followed his sale of 8.6% of the company's shares.

It said, "Mr Whelan remains committed to the long term future of JJB Sports and is selling the shares for personal financial reasons."

A JJB executive quoted in the Sunday Telegraph defended Mr Whelans action's, saying that "when he said that in January he genuinely believed it".

He added that the statement was supposed to reassure investors that Mr Whelan would not sell his shares piecemeal in the market.

Mr Whelan, who still owns Wigan Athletic football club, set up JJB Sports in 1971.

JJB Sports has about 430 shops in the UK.