Former Labour MP Paul Marsden has confirmed that his solicitors were examining evidence that his phone may have been hacked by a Daily Mirror journalist in 2003.
Marsden - who was elected for Labour in 1997 before defecting to the Liberal Democrats - said he was keen to pursue court action.
If legal action goes ahead, Marsden will be the first figure to push the phone hacking scandal beyond the confines of News International, which has been mired in the controversy since News of the World royal correspondent Clive Goodman was jailed in 2007 for hacking along with private investigator Glenn Mulcaire.
Marsden's revelations come as Keir Starmer, the Director of Public Prosecutions, confirmed yesterday that prosecutors would expand their review of evidence gathered during the phone hacking inquiry to include fresh claims swirling around the scandal.
Starmer said any evidence from "recent or new substantive allegations" will be assessed by a senior barrister as part of an ongoing inquiry into material already held by Scotland Yard.
Marsden told BBC Radio 4's PM show yesterday: "I have started legal inquiries through my solicitors based on evidence and information which we received that I may have been the victim of phone hacking back in about 2003."
"We have started those legal inquiries with a specific journalist and also the Mirror Group.
'If it turns out to be true, I would like it exposed in a court of law. I want to know the truth."
Marsden hit the headlines in December 2001 when he quit Labour, voicing opposition to the Afghanistan war and anti-terrorism legislation and saying he was "sick and tired" of the government.
His career took a colourful turn in November 2003 when it emerged that he had posted poems on his internet site which referred to his infidelity.