A battle between two billionaires for a trophy estate in the Golden Vale has been at the heart of five days of witness testimony and legal argument in the High Court, with many more days to come.

Coolmore supremo and former senator John Magnier and US-based construction tycoon Maurice Regan both coveted the 751ac Barne Estate, owned by the Thomson-Moore family for some 400 years.

An alleged oral agreement and handshake deal between John Magnier and Richard Thomson-Moore at Coolmore House on 22 August 2023 would have seen the estate sold to Magnier for €15m.

However, John Magnier alleges that the Barne side broke what he called a binding deal, as well as a later exclusivity agreement by agreeing to sell the estate to construction magnate Maurice Regan in October 2023. Regan agreed to pay €22.25m for the estate, some €7m more than Magnier’s €15m.

The High Court case was taken by John Magnier, his son John Paul Magnier and daughter Katherine Wachman, against Richard Thomson-Moore, Barne Estate Ltd, and two Jersey-registered companies, IQ EQ One and IQ EQ Two.

Among the key points being debated in court 29 is whether any deal to buy Barne required approval from Barne Estate trustees, whether the trustees were phoned on the night, and whether Richard Thomson-Moore had authority from them to conclude a deal.

John Magnier has further claimed that the deal verbally agreed with Richard Thomson-Moore and on which they shook hands, left it open to him to buy either the land itself or shares in the company that owns the land, Barne Estate Ltd.

John Magnier and his farm manager Joe Holohan claimed in court that auctioneer John Stokes told them they were calling the trustees, having claimed Richard Thomson-Moore said it in their earlier written statements, which they later amended. The court heard that Anna Thomson-Moore, Richard Thomson-Moore’s wife, will give evidence that she said, on a number of occasions on 22 August, that trustee approval would be required.

Senior counsel Martin Hayden acting for Richard Thomson-Moore, alleged in court that John Magnier knew “full well” he had no binding agreement.

The Coolmore boss outlined to the court three reasons why he and his son delivered €50,000 in cash to Richard Thomson-Moore on 7 October 2023. Number one, he said, was that Coolmore was being allowed in to farm the land at Barne Estate before the sale was completed. Number two, he said, was because Richard Thomson-Moore was “resisting Regan’s bid” and was going to “stay honourable”. The third reason was because he said auctioneer John Stokes told him they were “strapped for cash”.

In court last week John Magnier alleged that billionaire Maurice Regan had earlier attempted to persuade the Coolmore boss to step away from purchasing Barne Estate and keep land prices in Tipperary down. John Magnier told the court that he had previously stood down from a land sale at Maurice Regan’s request, when Mr Regan “wanted to relocate a neighbour”.

Honour and simplicity are two traits that have frequently cropped up in the case.

John Magnier told the court that his good name was very important to him and that he came to court for protection, “not to be slaughtered”.

He outlined how he leaves much of his business wrangling to his key Coolmore advisers, describing legal and financial intricacies as being “above my pay grade”.

“I don’t understand this legal jargon like I should,” he said.

“I left school when I was 15. I haven’t got a very good education. I employ people to do these things on my behalf. They’re better than I am,” he told the court.

He told the court that his adviser Eddie Irwin handled most of the legal and contract details for Barne Estate, which are now being examined in minute detail.

Mr Irwin is expected to give evidence in the coming days.