Alexei Navalny is Vladimir Putin’s most prominent opponent and as such, no stranger to threats against his life.
In 2017 Navalny was attacked by a pro-Kremlin supporter who threw a chemical substance in his eye, leaving him partially-blind, and last year he was rushed to hospital from his prison cell, again for suspected poisoning.
Doctors said he suffered a severe allergic reaction caused by toxins.
Alexei Navalny is seen at a Siberian airport before boarding the plane where he was taken ill. Pic: @djpavlin
Through his Anti-Corruption Foundation Navalny has sought to expose fraud and illicit activity by members of Putin’s United Russia party, which he famously called “the party of crooks and thieves”.
In turn Russian authorities have levied money-laundering allegations against him, imprisoned him on spurious charges and raided the homes and offices of his associates in a crackdown on his pro-democracy movement.
Navalny has claimed to be the target of Russian troll farms run by Putin allies and is regularly hassled on the streets of Moscow.
The 44-year-old was raised in a series of towns on the outskirts of Moscow, the son of factory owners.
Holidays were often spent near the Ukranian town of Chernobyl where his father and relatives grew up.
Stories of their mistreatment after the nuclear explosion, and theft by local party members, fuelled Navalny’s opposition to the government.
Alexei Navalny marching in memory of murdered Kremlin critic Boris Nemtsov in February
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In 2013 he came second in Moscow mayoral elections and then spent the following year under house arrest on fraud charges.
During that time he became aware of the impact memes and viral videos could have.
Navalny weaponised the internet and took on Putin: A 2017 video exposing an empire of palaces belonging to former Prime Minister Dmitry Medvedev was viewed more than 30 million times.
Alexei Navalny in court in Moscow in 2017 after being arrested at a demonstration
Using social media and blog sites, he has successfully created a nationwide network of supporters that has grown and threatened Putin’s power despite campaigns of intimidation and violence against them.
Another tactic of Navalny’s has been to buy a small number of shares in Russian oil companies or banks and then ask awkward questions at AGMs.
But, as successful as he has been in building a movement against Putin, Navalny has never taken him on head-to-head.
In 2018 he was barred from running against Putin in presidential elections, leading to protests on the streets of Moscow.
Navalny carried out on stretcher
Poisoning is a common tactic used by Russia to eliminate opponents – the 2006 assassination of Alexander Litvinenko and March 2018 attack on Sergei and Yulia Skripal in Salisbury are high-profile examples of the lengths Russian intelligence services will go to.
Alexei Navalny isn’t universally popular amongst anti-Putin groups – some believe he’s too much of a nationalist and question his links with the US – he spent a year at Yale University in 2010.
But he is the face of Russian opposition and as long as he remains a thorn in Putin’s side, Navalny can expect to be targeted by a state that doesn’t take well to criticism.