Taxpayers will fund a refurbishment of two toilets used by peers and VIP guests at the Palace of Westminster - at an "eye-watering" cost of up to £100,000.
The men's and women's lavatories in the House of Lords are in "unacceptable condition for the high profile area they are in", according to an advert inviting contractors to bid for the work.
The rooms are not the only toilets in the building and are not particularly big, with one cubicle and two urinals in the men's toilets and one cubicle plus a hand basin in the women's.
However, the costs will not be helped by the fact that the work must comply with English Heritage requirements for Grade I listed buildings.
It includes replacing "historic oak panelling", minor demolition work, new decorations and new sanitary equipment.
The toilets - used by peers, staff and visitors from delegations from overseas parliaments - were built in 1937.
They have reached the "end of their serviceable life" and give a "poor image" of the Palace of Westminster, the tender document adds.
Twelve companies have expressed an interest in carrying out the work and a House of Lords spokesman said the winner of the contract would be chosen "with a determined focus on value for money for the taxpayer".
Taxpayers' Alliance chief executive Matthew Sinclair said the sums involved were "eye-watering".
"A family could afford to build themselves a home for this much cash," he said.
"The parliamentary authorities need to ensure refurbishments to the estate provide value for taxpayers' money."
The work, which will ensure the toilets in the Salisbury Room area comply with disability access legislation, is estimated to take six weeks.
The last revamp took place more than 20 years ago, and the contract is valued by the House of Commons authorities at between £90,000 and £100,000.