A spokesman for Denis O'Brien was saying nothing yesterday about the billionaire businessman's decision to take a High Court action against the Revenue Commissioners and two of its officials.

The move comes hot on the heels of the High Court’s ruling in his favour in relation to whether or not he should have to pay a €56 million-plus capital gains tax bill arising from his sale of his interest in Esat Telecom/Digifone in the early noughties.

Ms Justice Mary Laffoy agreed with a Revenue Appeals Commissioner that O’Brien’s permanent home in the tax year 2000/2001 was Quinta de Lago, Almanscil, Portugal, not Ireland. At the urging of the Revenue, the issue had been referred to the High Court for review. Whether the new proceedings by O’Brien have any link to that case, which centered on whether a house he owned on Dublin’s Raglan Road was a permanent home within the meaning of Article 4.2 of the Double Taxation Convention, is not (yet) known.

Some years ago, the address used by O’Brien in his corporate filings changed from Portugal to Tigne Street, Sliema, Malta. However, in a recent filing to Companies House in the UK, O’Brien has informed the register that his new address in Malta is an apartment on Ghar 10 Oud Street, Sliema. The filing was made in relation to the affairs of Doncaster Rovers Football Club Ltd, the company that has an interest in the site of a former football stadium in Doncaster, and which was the subject of extended hearings at the Moriarty Tribunal.

As he made clear in a recent successful libel action he took against the Irish Daily Mail, O'Brien pays tax here on all his Irish taxable earnings, which must make him a figure of interest to the Revenue from an earnings point of view.

We don’t know yet what the issue is behind his latest move, but he must be up there among the Revenue’s more interesting customers, given how long the capital gains tax issue stretched on for, and his decision now to take on the role of plaintiff in a case where the defendent is Dublin Castle.

The case has not been listed for mention yet, nor have any filings been registered. Every move will be watched closely.