Nadine Dorries, the Conservative frontbencher who claimed the Daily Telegraph's revelations on expenses could drive MPs to suicide, has had her blog shut down by lawyers acting for the newspaper.

The virtually unprecedented action against a serving MP came after Dorries was disowned by her party leader, David Cameron, and described as "wacky" by senior Conservative sources. She had claimed that MPs were being "tortured" by the Telegraph's dripfeed of revelations.

Nadine Dorries. Photograph: Guardian

The newspaper is understood to have acted after she made further allegations concerning the motivation of the newspaper's proprietors, Sir David and Sir Frederick Barclay. Withers, the lawyers acting for the Barclay brothers, are understood to have instructed the takedown, invoking the acceptable user policy used by internet service providers to protect themselves against libel action provoked by comments on websites they host.

Dorries was defended by fellow bloggers yesterday, including Iain Dale, who said he had not agreed with Dorries's allegations "but so what? I defend her right to say it, no matter how ill advised I think some of it might have been for her personally. Can it really now be illegal or libellous to question a newspaper's agenda and motives, or those of its owners?"

As an MP, if Dorries chose to repeat her allegations on the floor of the Commons she could expect to be covered by parliamentary privilege, which protects MPs against being sued for libel and is designed to preserve their right to free speech in the public interest. But privilege does not cover comments made outside the chamber.

Dorries, a former nurse best known for her attempts to change the law on abortion, has herself been targeted by the Telegraph. It forced her to disclose to constituents that she lives partly in the Cotswolds despite designating a rented house in her Mid Bedfordshire constituency as her second home.

She has been the only MP so far to pre-empt the newspaper by publishing on her blog the letter it sent to her outlining its allegations.

In an article for the Independent newspaper published yesterday, Dorries said the investigation was becoming a "witch-hunt" and attacked the Telegraph for "picking off a few MPs each day, emailing at noon, giving five hours to reply, recording the conversation, not allowing them to speak, telling them they are going to publish anyway".

Dorries is herself threatening legal action over the leaked Damian McBride emails discussing smearing senior Tories, which she says contained false and scurrilous allegations against her.

A spokesman for the Telegraph yesterday declined to comment.