The arrests began even before the protest started. A woman was prised from a street bench. A group of pensioners were seized as they walked along the street. A young man was grabbed as he left a bank. There seemed to be little logic at play.

Mere presence near the proposed demonstration point was enough to be wheeled away, often violently, to the police vans.

According to independent monitors OVD-Info, 89 people had been detained by the 2pm start. That figure rose to 1373 by the evening.

The unauthorised protest was organised in response to the exclusion of opposition candidates from September’s Moscow city elections. A number of those candidates were among the arrested.

Authorities were taking no chances. The night before, metal barriers appeared on Tverskaya Street, the main thoroughfare that runs from the Kremlin and past the mayor’s office, the planned location of the rally. An unprecedented number of men in uniforms — riot police, national guard and ordinary policemen — appeared in central Moscow. Dozens of police vans stood ready to absorb the expected numbers of arrested.

By the start of the meeting, police had sealed the area immediately in front of the mayor’s office. Then, they moved in formation to divide the protest and push crowds away into side streets. The protesters resisted. Truncheons were used against them. There were reports of electronic weapons. At least one woman, who it later transpired was a municipal deputy called Alexandra Parushina, was left bleeding after being hit on the head. She was seen wiping her blood on riot officers’ uniforms.

“Let them understand that our blood is on them,” Ms Parushina told a reporter working for Dozhd, Russia’s last remaining independent online television channel.

A few hours later, a team of police officers descended on Dozhd’s studios in northern Moscow. It was not immediately clear whether the channel's decision to remove its paywall specially for coverage of the protest played a role in the visit.

By evening, the demonstration moved on to Trubnaya square, a public space that has over the past two weeks served as a protest meeting point. Opposition leaders had hardly begun making speeches when the gathering was violently dispersed by riot police. At least one man was seriously injured in that operation.

The harsh police tactics formed only part of an operation against these, the wildest protests Russia has seen in seven years.

In the lead up to Saturday’s rally, authorities also arrested Alexei Navalny, Russia’s most prominent opposition politician. They conducted night-time raids at the homes of his press officer, lawyers, and all the other excluded candidates. One candidate, Konstantin Yankauskas, was not home when officers called, and his parents declined to heed their request to enter. Undeterred, authorities sent another group of officers to the home of Mr Yankauskas’ 80-year-old grandmother.

Gennady Gudkov, an opposition politician, former Duma deputy and KGB officer, likened the pre-protest operation to the return of Stalinism. “We are back in 1937,” he wrote on Twitter.

Vladimir Putin's Photo ops – Russia's Man of Steel? Show all 20 1 /20 Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin is pictured with a horse during his vacation outside the town of Kyzyl in Southern Siberia on August 3, 2009. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin aims at a whale with an arbalest to take a piece of its skin for analysis on the Olga Bay, some 240 kilometres north-east of Nakhodka on August 25, 2010. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin plunges into the icy waters of lake Seliger during the celebration of the Epiphany holiday in Russia's Tver region AFP/Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin (top) takes part in a judo training session at the "Moscow" sports complex in St. Petersburg, on December 22, 2010. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin works out at a gym at the Bocharov Ruchei state residence in Sochi on August 30, 2015. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin fishes in the remote Tuva region in southern Siberia. The picture taken between August 1 and 3, 2017. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin (L) and the leader of the Night Wolves biker group, Alexander Zaldostanov (R), also known as the Surgeon, ride motorcycles on August 29, 2011 at a bikers' festival in the Black Sea port of Novorossiysk, Russia. Putin described leather-clad bikers as brothers and boasted of the "indivisible Russian nation" after roaring into a biking rally on a Harley Davidson. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin wears glasses as he visits the Technology Park of the Novosibirsk Academic Town in Novosibirsk on February 17, 2012. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin rides a horse during his vacation outside the town of Kyzyl in Southern Siberia on August 3, 2009. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin holds a pistol during his visit to a newly-built headquarters of the Russian General Staff's Main Intelligence Department (GRU) in Moscow, 08 November 2006. ?Some countries are seeking to untie their hands in order to take weapons to outer space, including nuclear weapons,? Putin said at the Chief Military Intelligence Department on Wednesday. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin sits inside a T-90AM tank during a visit to an arms exhibition in the Urals town of Nizhny Tagil on September 9, 2011 Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin wears a helmet and the uniform of the Renault Formula One team before driving a F1 race car on a special track in Leningrad region outside St. Petersburg on November 7, 2010. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin guides a boat during his vacation in the remote Tuva region in southern Siberia. The picture taken between August 1 and 3, 2017. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin hunts fish underwater in the remote Tuva region in southern Siberia. The picture taken between August 1 and 3, 2017. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin is seen at the Russian boxing team training club after casting his vote for the Russian Presidential election, 14 March 2004 in Moscow. Putin coasted to a landslide victory with 69.0 percent of the vote in Sunday's election, according to the first exit poll aired on Russian television moments after voting ended across the country's 11 time zones. AFP/Getty Images Vladimir Putin's Photo ops – Russia's Man of Steel? Russian President Vladimir Putin poses for a picture inside the Tupolev-160 strategic bomber jet at the Moscow's Chkalovsky military airport, 16 August 2005. President Vladimir Putin took off from Moscow for a supersonic flight in a cruise-missile carrying Tupolev-160 bomber jet, the latest in the Russian leader's action-packed public appearances. After a health check, Putin donned a flight suit and took the commander's position in the strategic bomber, which was piloted by Major General Anatoly Zhikharev, with a colonel and a lieutenant colonel in charge of navigation, Russian media reported. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? A picture released on March 6, 2010 shows Vladimir Putin look through binoculars in the Karatash area, near the town of Abakan, during his working trip to Khakassia, on February 25, 2010. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin measuring a polar bear on the island Alexandra Land, part of the Franz Josef Land archipalego in the Arctic Ocean. Putin, better known in the West for his tough-guy image, expressed concern for the fate of Arctic polar bears threatened by climate change. "The polar bear is under threat. Their population is currently only 25,000 individuals," Putin was quoted by Russian news agencies as saying Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Vladimir Putin carries a hunting rifle during his trip in Ubsunur Hollow Biosphere Reserve in Tuva Republic in this undated picture released on October 30, 2010 by RIA Novosti news agency. Getty Vladimir Putin's Photo ops – Russia's Man of Steel? Russian President Vladimir Putin pilots a motorized hang glider while flying with cranes as he takes part in a scientific experiment as part of the "Flight of Hope", which aims to preserve a rare species of - cranes on September 5, 2012. At the helm of a motorized hang glider that the birds have taken as their leader, Putin made three flights - the first to get familiar with the process, and two others with the birds. AFP/Getty

On the day, authorities warned of arrests and violence. Sergey Sobyanin, Moscow’s mayor, claimed intelligence of “impending provocations” posing a “threat to … life”. Those who came anyway would be dealt with “according to the established procedure”, he said. Journalists were also asked to register their intention to cover the protest with the authorities.

Such hints likely affected the numbers attending the demonstration, which were down compared to the sanctioned demonstration last week. Given the dispersed nature of the protest, it was difficult to count. Police estimates said 3,500 attended, though such figures are traditionally underestimated.

Observing the extent of the clampdown, it was easy to forget the actual cause of the political storm.

On paper, the stakes are tiny: just a few places in the Moscow city government, a body with few real powers. But the Kremlin made an early decision not to allow opposition candidates near the ballot papers even there. On the eve of elections, authorities introduced new rules increasing the number of verified signatures independent candidates needed to register to approximately 5000. The hope had been that candidates would be unable to reach the required numbers in time. When most of them did, Moscow's local election committee ruled a large number of the signatures to be invalid, removing all but the most placid of candidates.

That was the moment that a local problem became a national crisis — and one that is certain to grow, says Tatyana Stanovaya, an analyst at the Carnegie Moscow Centre.