Twitter was tonight told to act promptly to close down a spoof account set up to abuse a senior Liberal Democrat MP.
Sir Bob Russell said a false account had been set up under his name by someone with a "sick, evil and warped mind" to post "vile" comments under his name.
Raising a point of order in the Commons, the MP for Colchester asked Speaker John Bercow what he could do about the problem.
The Speaker said he understood Twitter would promptly shut down spoof accounts set up to impersonate MPs. But he warned he would be prepared to revisit the issue if bosses at the social networking site did not act quickly.
Sir Bob said: "A Twitter account has been set up in the name of Bob Russell MP but I assure you that it is not I that has done so.
"Throughout today it has been filled with vile comments from someone with a sick, evil and warped mind. This has to be viewed in the context of three years of dirty tricks in Colchester against me by three immature young men who are all members of the same party.
"This has involved a spoof YouTube video of me and letters to newspapers with false names and addresses. Mr Speaker, can you guide members about what can be done in case of impersonation of a Member of this House?"
Mr Bercow replied: "It is clearly unacceptable that you are subject to this form of harassment. It is not however a matter of order for the Chair.
"I understand, however, that the companies which host such accounts will usually respond promptly to any example where 'MP' is used illegitimately. For tonight, I shall leave it there."