Novichok poison victim Charlie Rowley plans to sue the Russian state for a six-figure payout.
Mr Rowley – who lost his girlfriend Dawn Sturgess and was in a coma for two weeks – has hired top injury lawyer Patrick Maguire.
Mr Rowley said: “This has affected my life in a huge way. I want justice.”
It is understood he could be in line for thousands if he wins the case.
Mr Maguire said: “Dawn and Charlie were both innocent victims caught in the crossfire of the Salisbury poisonings which rocked the whole community.
“Charlie continues to suffer serious side effects from the toxin he ingested, but says his greatest concern is uncovering the truth about what really happened.
“There are still so many unanswered questions and that is why he has instructed us, to help him get those answers. He feels he owes that to Dawn.”
Mr Maguire, who has represented victims of the 2017 London Bridge and Westminster terror attacks, is proposing the possibility of suing the Russian government, among other options.
Dawn died aged 44 on July 8 last year, a week after Charlie, 46, unwittingly gave her a bottle of novichok, disguised as Premier Jour perfume, after he found it in a charity bin.
Charlie miraculously survived after 10 days in a coma, before later suffering strokes and meningitis .
He is now rebuilding his life with his new girlfriend Kim Mahoney, 46, but continues to suffer medical problems and flashbacks which have left him suicidal.
Two Russian agents have been charged with attempted murder. The attack was said to be a bungled attempt to kill Russian ex-spy Sergei Skripal, who was living in Salisbury, and his daughter Yulia.
But President Vladimir Putin’s government denies involvement and refuses to hand over the suspects.
Mr Rowley met Russia’s ambassador Alexander Yakovenko in April.
The diplomat claimed it could have been a plot to frame Russia.
