Directors at the UK's top 100 companies have built up a pensions pot worth almost £1bn, a report has found.
The report could lead to more "fat cat bosses" claims
On average, such directors can retire at 60 with a pension worth almost £3m, paying out £168,000 a year, research by the Trades Union Congress (TUC) found.
The largest final salary pension scheme was worth £4.9m, the report said.
Meanwhile, the proportion of executives in final salary schemes remained above 80%, while many firms had closed such schemes for its staff, the TUC added.
"Britain's boardrooms and business lobby groups have failed to tackle upstairs-downstairs style company pensions," said TUC general secretary Brendan Barber.
"If bosses were in the same scheme on the same terms as staff, they would still build up massive pensions compared to employees, but they would be fairer. It would also help reduce their company pension deficits."
According to the report, final salary pensions build up almost twice as fast for directors as for ordinary employees - as a result it takes staff an average of 40 years to reach full pension compared to 20 years for directors.
It also found that companies paid in up to 35% of salaries into directors' pensions, compared with the average for all employees of 6.6%.
More than three quarters of the companies surveyed said they allowed executives to retire on a full pension at the age of 60.
"This research gives the lie to the argument that bosses can't afford to contribute to decent pension schemes - they'd just prefer to keep them to themselves," said the head of the Rail Maritime Transport Union (RMT), Bob Crow.
"All our experience tells us that it is workers who are in trade unions and are prepared to fight who will keep and improve their workplace pension rights."
The TUC's annual survey - which began in 2003 - comes just days after similar findings from the Labour Research Department (LRD).
LRD accused executives of enjoying "super enhanced" pensions as workers faced up to a tough retirement.
It found that bosses at the UK's top firms retire on a pension worth at least 71 times that of the basic state pension for a married couple - with at least 112 directors currently entitled to a pension worth at least £200,000.