Cleaners at the Houses of Parliament are the lowest paid in Europe, research has shown.
Cleaners are demanding £6.70-an-hour
The revelation comes as union leaders threatened a further round of strikes unless a long-running dispute over wages was settled by Christmas.
Research by the Transport and General Workers Union (T&G) showed wages of parliament cleaners in Europe ranged from £9.20-an-hour to £5.30.
This compares to £5.20 in the UK. Talks with contractors are due next week.
The cleaners have already staged two 24-hour strikes. They are demanding £6.70-an-hour, a pension, and more holidays.
CLEANERS' RATES OF PAY
Cleaners from across Europe visited Parliament on Wednesday to show their support.
The UK cleaners are the only ones in Europe without any sick pay or pensions, and have just 12 days holiday, compared with 30 in Denmark and five weeks in Holland and Sweden.
Jack Dromey, deputy general secretary of the T&G, said the civil servants and politicians responsible for setting pay rates should be "ashamed" that UK cleaners were at the bottom of the European league.
"If the parliaments of Europe can afford decent pay, pensions, sick pay and holidays, then so should the Parliament in one of the most expensive cities in the world."
Mr Dromey said the union stood ready to reach a settlement next week, but he urged Parliament not to "wash its hands" of responsibility, adding: "Let us hope we reach a settlement before Christmas.
"If the talks break down next week industrial action will be resumed."