Parliamentary computers have been used to log onto crisis hit adultery website Ashley Madison.
The site, which has the slogan Life Is Short. Have An Affair, was targeted in July by hackers who released details of millions of its users.
But despite the controversial nature of the site, computers used by members of parliament, peers and their staff accessed it 26 times during the last year.
In a response to a Freedom of Information request by the Press Association, Parliament said all attempts to access the website on their network were blocked, but staff were permitted to access the internet for personal use in non-working hours.
This includes MPs, members of the House of Lords, their staff and staff of the House administrations.
Following the hack, SNP MP Michelle Thomson was forced to deny any connection with the site after an email address allegedly linked to her appeared among the data posted.
The MP for Edinburgh West said the "out-of-use" email address had been "harvested by hackers".
Last month the boss of the website Noel Biderman, the self-proclaimed King Of Infidelity, stepped down after the leak which saw the details of up to 37 million cheating spouses revealed.
This included the names, addresses, phone numbers and credit card details of users - including reportedly 1.2m people living in the UK - on the dark web.
UN officials and even Vatican employees have reportedly have been exposed in the scandal, which has been linked to two suicides in Canada.
The response said information going further back in time was not available because data is only held on the servers for one calendar year.