Ms Dorries gained an official apology over the smears
Conservative MP Nadine Dorries is taking legal action against ex-Downing Street spin doctor Damien McBride over e-mail smears, sources have confirmed.
The Mid-Bedfordshire MP will also sue Derek Draper, who formerly ran the Labourlist website.
It is understood that Ms Dorries is also taking legal action against No 10, but papers have not yet been served.
Mr McBride, who sent the unfounded smears to Mr Draper, resigned after they were made public.
The e-mails also featured unfounded personal attacks on Conservative leader David Cameron and shadow chancellor George Osborne.
Mr Draper never published the claims on a gossip website he was planning to set up called Red Rag.
But they came to light after the e-mail found its way to Westminster blogger Paul Staines, who writes under the name Guido Fawkes.
Ms Dorries secured a personal apology from Prime Minister Gordon Brown when she confronted him over the smears in the Commons in April.
This followed Ms Dorries, a former nurse who has been an MP since 2005, claiming that Downing Street had a "cesspit" culture.