The National Union of Mineworkers today asked the High Court to decide whether it is obliged to meet the cost of former leader Arthur Scargill staying in his London flat.
Mr Scargill, 74, who was the NUM's president for 20 years until July 2002, has occupied the Barbican apartment, rented from the Corporation of London, since June 1982.
The rent and associated expenses were paid by the union until 2011, except for a period between 1985 and 1991 when Mr Scargill met them out of his own pocket.
The NUM's counsel, Nicholas Davidson QC, said that the case was not about whether anyone thought that any particular obligation ought to exist - but whether it did exist.
If it did, Mr Scargill was entitled to have the benefit of it.
He told Mr Justice Underhill that the action concerned whether the union was obliged to meet the costs of the use of the flat for the rest of Mr Scargill's life and the lifetime of his widow, should he leave one.
Other issues were whether his fuel allowance for his house in Barnsley, Yorkshire, had a limit, other than simply the total amount of his consumption in the year, and whether the union was obliged to pay - for his lifetime - the cost of his security system there and the preparation of his annual tax return.
Mr Davidson said that the litigation, which will look at documents dating back 30 years, was concerned with identifying what terms were agreed between duly authorised representatives of the NUM and Mr Scargill.
Mr Scargill's counsel, Timothy Pitt-Payne QC, argues that he is entitled to the retirement benefits under the terms of his successive contracts of employment with the NUM and pursuant to various decisions of the union and its constituent bodies.
He is seeking declarations that the NUM is obliged to pay, plus payment of the Barbican expenses from June 2011 to date and payment of the fuel, security and accountancy costs incurred by Mr Scargill since they were suspended in April 2010.
The hearing, which is expected to hear evidence from a number of witnesses including Mr Scargill, is due to last a week.
The hearing was adjourned until tomorrow.