An increase in the number of workers doing unpaid overtime in the public sector has almost entirely been driven by 250,000 more women working extra hours for free, according to a study by the TUC.
In 2003, more men than women did unpaid overtime in the public sector, but the position has been reversed, the research found.
One in four public sector workers puts in at least an extra hour a week, the TUC said.
Around one in six staff in private firms worked extra hours for no pay, a figure which has largely remained unchanged over the past decade, although the amount of unpaid overtime has increased.
More top news
The Cosby Show star, 80, was found guilty of three counts of aggravated indecent assault.
The Government's stance risks a negotiating car crash with the EU, as it refuses to acknowledge risks over the Irish border.
Sunshine and a soaking