FORMER Russian double agent Sergei Skripal is in hiding following a suspected poison plot in Salisbury, Wiltshire, a year ago.

It is the latest tragedy to befall his young family after both his wife and son died in mysterious car crashes. Here's what we know...

3 Former double agent Sergei Skripal is fighting for his life after a suspected poison plot Credit: AFP or licensors

Who is Sergei Skripal?

Born on June 23, 1951, Sergei Skripal was a Russian officer who was convicted of spying for the United Kingdom in 2006.

In 2004, Sergei Skripal was arrested by Russia for trading sensitive information with UK intelligence agency, MI6.

Skripal was accused by Russian prosecutors of working for MI6 in the late 1990s and passing secrets to the British using a James Bond-style spy rock.

At the time, he was serving in the Russian Ground Forces and was nicknamed 'the Spy with the Louis Vuitton bag'.

How did Sergei Skripal's wife and son die... and was there a car crash?

Skripal, 67, who was found unconscious alongside his daughter Yulia, 34, has suffered two bereavements in the last seven years.

Mystery surrounds both the death of his wife Lyudmila aged 59 in 2012 and his son Alexandr, who was 43 when he passed away in 2017.

Their neighbours in Wiltshire claim Lyudmila was killed in a car crash but her death certificate says disseminated endometrial carcinoma, a form of cancer.

And although reports suggest his son died in a St Petersburg car crash two years ago, the family cleaner claims he passed away from liver problems.

3 Skripal, who was found unconscious alongside his daughter Yulia, pictured, suffered two bereavements in the last seven years Credit: AP:Associated Press

"I saw reports on the news that his wife had died in a car crash," the woman who cleans their Salisbury home was quoted as saying by MailOnline.

"That is not true, she died of cancer that she had when they moved to England. And his son died of liver problems, so I don't know where the car crash idea came from."

But his neighbour Blake Stephens, 22, said she "died in a car accident a while ago".

The BBC reported that Alexandr died from liver failure while on holiday in Russia with his girlfriend.

What is disseminated endometrial carcinoma?

Endometrial cancer is the most common type of the disease to affect the womb, according to Cancer Research UK.

It begins in the lining (endometrium) of the uterus, the hollows pelvic organ where fetal development occurs.

The disease is usually caught early because it "frequently produces abnormal vaginal bleeding", the Mayo Clinic says.

If endometrial cancer is discovered early, removing the uterus surgically often cures endometrial cancer.

3 Mystery surrounds both the death of his wife Lyudmila aged 59 in 2012 and his son Alexandr, who was 43 when he passed away in 2017 Credit: PA:Press Association

Why was Sergei Skripal arrested and how long was he in prison for?

Skripal was arrested in December 2004 and charged with "high treason in the form of espionage" and was found guilty.

The former spy was sentenced to 13 years in prison after Russia claimed he was paid $100,000 to extract classified information and state secrets.

He pleaded guilty at his trial but was later one of the four prisoners Moscow swapped in 2010 for spies in the US.

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It was reported that Skripal managed to return to Britain, but has been keeping a low profile for the last eight years.

The retired spy Colonel and a woman believed to be his daughter, Yulia, were both critically ill after being poisoned last year.

They were found slumped in the Maltings shopping centre in Salisbury after being exposed to an unidentified substance.