By Laura Gozzi & Vitaly ShevchenkoBBC News31 January 2024, 11:13 GMTUpdated 16 minutes agoImage caption, Boris Nadezhdin thanked his supporters as he submitted the signaturesKremlin challenger Boris Nadezhdin has announced that he has gathered enough signatures to run for president in Russia’s upcoming election. Known for his outspoken criticism of Mr Putin and Russia’s invasion of Ukraine, the former MP stated that he has submitted over 100,000 required signatures to the electoral authorities. The electoral commission now needs to review his application. If any irregularities are found with the signatures, the commission has the authority to disqualify the candidate. Independent politician Yekaterina Duntsova was disqualified in December due to 100 “mistakes” found on her form.Current President Vladimir Putin has already registered as an independent candidate for the March election, likely ensuring another six-year term. Shortly after the deadline to hand in the signatures, Mr Nadezhdin posted a photo of himself in front of several boxes containing papers with the signatures of his supporters. He expressed his gratitude, saying, “This is my pride – the work of thousands of people over many sleepless days. The result of the queues you stood in in the freezing cold is in those boxes,” on X, formerly Twitter.Thousands of Russians across the country have braved the cold to add their signature in support of his bid. Nominated to stand in the election by the centre-right Civic Initiative party in December 2023, Mr Nadezhdin, 60, served as a former local councillor and member of the State Duma in the pre-Putin era. He has frequently appeared on state TV channels, criticizing Russia’s war on Ukraine. In a nation where opposition figures have been imprisoned or even killed, his recent criticism of Mr Putin seems to have been tolerated thus far. Kremlin spokesman Dmitry Peskov previously stated, “We don’t see him as a rival,” when asked about Mr Nadezhdin.Earlier this month, Mr Nadezhdin told the BBC’s Newshour program that he is “not afraid” to run, though he remarked that elections in Russia “are not free and not fair”. Regarding his criticism of the war in Ukraine, he asserted that invading the country was a “fatal mistake” which “dragged [Russia] into the track of authoritarianism and isolation”. “First of all we should finish killing each other and then there will be long, long negotiations about the border,” he said.Even if Mr Nadezhdin is permitted to run, it is uncertain if he will be allowed to campaign freely.In Vladimir Putin’s Russia, candidates have previously been able to participate in elections without any real chance to win, and sometimes they do not even campaign against the incumbent. This perpetuates a facade of democracy, and in the case of Mr Nadezhdin, it would enable dissatisfied Russians to express their anger and frustration without threatening Mr Putin’s rule.Genuine opposition figures such as Alexei Navalny and Ilya Yashin have been handed lengthy jail terms in recent years. Others, like Kremlin critic Boris Nemtsov – for whom Mr Nadezhdin once worked as an adviser – have been killed. Since 2000, Russia’s political landscape has been dominated by Vladimir Putin. In 2020, a constitutional amendment was passed allowing him to extend his stay in power beyond 2024. A victory in March would extend his presidency until 2030. Furthermore, he could potentially serve an additional six-year term until 2036 if he chooses to run again.Video caption, Watch: ‘Putin has made mistakes’, Kremlin challenger says in BBC exclusive