Newcastle United owner and Sports Direct boss Mike Ashley came across as an "honest bloke" when giving evidence at a High Court trial, after being sued by a finance expert who says he reneged on a £15 million deal, one of his lawyers has told a judge.

Investment banker Jeffrey Blue says 52-year-old Mr Ashley promised to pay him £15 million if he used his expertise to double Sports Direct's share price to £8 a share, during an evening at a London pub four years ago.

He says Mr Ashley paid only £1 million and he wants £14 million damages.

Mr Ashley denies the claim and says Mr Blue is talking ''nonsense''.

The two men are fighting at a High Court trial in London.

Mr Justice Leggatt began overseeing the trial last week and has heard evidence from Mr Blue and Mr Ashley.

Lawyers are outlining closing legal arguments.

The judge is expected to deliver a ruling later in the year.

A barrister representing Mr Ashley on Wednesday told the judge that Mr Ashley had been "honest" when giving evidence.

"Mr Ashley was obviously robust and a larger-than-life character, " said David Cavender QC.

"But he was honest. He was an honest bloke - sometimes disarmingly so."

Mr Cavender said Mr Ashley was sometimes "irritated" by questions from a barrister representing Mr Blue.

"That is hardly surprising, considering the nature of the claim brought against him," said Mr Cavender.

"He is not a professional witness. He is not a banker or a lawyer and he was under extraordinary pressure."

Mr Cavender added: "It is not surprising that sometimes Mr Ashley was irritated and cross."

He said Mr Ashley had not come to court to lie and went on: "He came here to give evidence for two days because he does not believe there was any agreement with Mr Blue."