House of Commons officials have said it is unclear whether MPs, peers or other staff are responsible for the requests, which were revealed by a Freedom of Information request submitted by the Huffington Post.
They also said the figures may have been exaggerated by third-party software and websites that reload themselves. Which, incidentally, is an excuse this author attempted to use many years ago after he was banned from the Sixth Form IT centre.
There are odd discrepancies in the numbers which do lend some credence to their statement. In November last year, there were 114,844 attempts to access websites classed as pornographic, but just 15 in February this year.
UPDATE 04/09/2013 18.22:
This interesting post argues that the November spike was probably due to new definitions being added to the filtering software.
David Cameron has a big problem with porn. He recently argued it was "corroding childhood", and announced in July that most households in the UK would have pornography blocked by their internet provider unless they chose to receive it.
The UK's biggest internet service providers have agreed to the filters scheme, so it will cover 95% of homes. And evidently to the frustration of some, the House of Commons.
Jimmy Wales, the founder of Wikipedia, has told Channel 4 News the police should be given more resources to enforce existing laws.
He said: "The software you would use to implement this doesn't work. Additionally when we use cases of a paedophile who's been addicted to child porn videos online, you realise all that Cameron's rules would require him to do is opt in and say, 'Yes, I would like porn please'."