Sports Direct founder Mike Ashley would "take a nap" under the table during meetings he found boring, a London court was told on Monday (3 July).

The claim comes from investment banker Jeffrey Blue, who has sued the tycoon alleging Ashley did not hold up his end of the bargain on an agreement between the pair.

The issue stems from a conversation between Ashley and Blue, which allegedly took place in the Horse & Groom, a London pub, in 2013. The latter maintains the former promised to pay him £15m ($19.5m) if Blue agreed to use his expertise to double Sports Direct stock price to £8 per share within three years.

At a High Court hearing in the capital, barrister Jeffrey Chapman QC, who heads Blue's legal team, told Mr Justice Leggatt that Ashley's business practices contravene "business orthodoxy".

The controversial tycoon, whose fortune is worth in excess of £2 billion ($2.7bn), allegedly lay under tables to take a nap during work meetings he found boring and played "spoof", a drinking game, to decide who would pay for an investment bank's fees.

Ashley, aged 52, who remains Sports Direct's largest shareholder, refutes the claims, branding them "extremely vague".

"I will have made so much money it doesn't matter," Ashley is alleged to have said.

However, the Newcastle United owner reportedly paid only £1m to the investment banker.

"Mr Ashley's business practices fly in the face of business orthodoxy," Chapman told the judge in written opening remarks.

"Mr Blue refers to Mr Ashley lying underneath tables in meetings he found to be boring to 'take a nap', playing a game of spoof to resolve who ought to pay Merrill Lynch's legal fees (totalling £750,000) and lavishly entertaining Sports Direct's non-executive directors."

The court papers also claim Ashley "often conducts business, discussions and concludes business agreements orally and informally, including while consuming alcohol."

The claim states Sports Direct's directors held a senior management meeting once a week at The Lion Hotel in Worksop, a short drive away from the firm's headquarters in Shirebrook, Derbyshire.

According to the papers, the meeting normally kicked off "in the bar area at around 8pm, with Mr Ashley drinking alcohol at the bar while in discussion with the management."

Following a meal served at 10.30pm, the meeting would then last until between 1am and 3am.

"Ashley made decisions at those meetings having consumed alcohol and sometimes considerable amounts of alcohol," the papers claim.