Justice Mary Laffoy has reserved judgment in the High Court in a challenge taken by the Revenue to a decision made by an Appeal Commissioner relating to the businessman Denis O'Brien.

The Appeal Commissioner, Ronan Kelly, found in 2003 that a house at 6 Raglan Road, Dublin 4, purchased by Denis O'Brien in 2000 was not a 'permanent home' under the Ireland/Portugal Double Taxation Convention.

Revenue then withdrew an assessment to capital gains tax of €57.8m in the tax year 2000/2001.

This arose from the sale by Mr O'Brien of shares in Esat Telecom.

Counsel for the Revenue, Anthony Collins SC, said the Appeal Commissioner had 'erred in law' in not recognising that someone could have two permanent homes under the Convention.

It said it had 'conflated' the concept of a permanently available home and a principal private residence.

Counsel for Denis O'Brien, Dermot Gleeson SC, said the property at Raglan Road was purchased as an investment.

He said Mr O'Brien's family had moved to Portugal and did not have a home in Dublin during the tax year of 2000/2001.

He added that "no stick of O'Brien furniture ever went into this house."