MPs are unable to discuss the Sexual Offences Bill because of their new email filtering software.

The system, introduced last month after MPs complained of being inundated with pornographic and rude spam, blocked more than 900 emails in its first week, according to the BBC.

The filtering software is proving too restrictive and is causing "chaos", one MP told the BBC.

Liberal Democrat spokesman Paul Tyler explained that the system is blocking parts of the Sexual Offences Bill being sent to parliamentary email addresses, as well as a Liberal Democrat consultation paper on censorship.

The system was installed a month ago without any warning and with no consultation, complained Tyler. He called for it to be suspended until all the wrinkles are ironed out.

But the House of Commons claimed that any emails blocked by the filter can be released instantly with one phone call to the help desk.