The problem has become so serious that a filter is being placed on the politicians' Internet connection to stop the material coming through.

Page after page of highly offensive material is displayed on the screen without any mechanism for switching it off

Brian Iddon

Labour's Brian Iddon said that many MPs have been receiving the "unsolicited" porn via the parliamentary network.

He said if one particular type of email is "accidentally opened, page after page of highly offensive material is displayed on the screen without any mechanism for switching it off".

'Filter mechanism'

During business questions, he told Commons leader Robin Cook: "For more than six months now, many MPs have tried to stop this through the usual channels, but have failed.

"Can you lend a hand and ask the network to purchase the necessary filters that will stop this?"

Mr Cook said he agreed with Dr Iddon about the "offensiveness of the material", stressing that secretaries and assistants "may encounter it more frequently".

Dr Iddon said he had found 'highly offensive' material.

The matter has been discussed at a meeting of the Commons Speaker's Panel, he said.

"I understand that the decision has been taken to acquire the necessary filter mechanism to make sure that MPs are protected and that our constituents are protected from the misuse of channels of communication that are there to enable members to respond to their correspondence and to serve their constituents properly."

It is not the first time an MP has raised concerns about their easy access to pornography at the Commons.

'Disturbing material'

Two years ago, Conservative Desmond Swayne told MPs it was only the Commons division bell that stopped him from lingering with a sense of "fascination" over a porn site.

He stunned his colleagues as he told them that following a constituents' complaint he was "without any ingenuity at all, or indeed any use of passwords and security, able to access quite a number of pornographic sites".

Most of the material was "little more titillating" than the phone cards offering sexual services in telephone booths across London, though he was also "able to access some very disturbing material, profoundly corrupting material which I think is extraordinary that it's so easily accessible".

At the time he asked ministers to look at whether it was "desirable or technically feasible" to take measures which would restrict the access of pornographic material to vulnerable people.