Lyubov Sobol, one of the only Russian protest leaders not yet to have been arrested, was among hundreds detained by riot police during a demonstration in Moscow.

A group of approximately 15 riot police descended on the politician, currently on day 21 of a hunger strike, shortly after she left her central Moscow campaign headquarters for the start of Saturday’s rally.

Ms Sobol, a close associate of Russia’s most prominent opposition politician Alexei Navalny, has been protesting against the exclusion of opposition candidates from Moscow city elections planned for September. After a dramatic struggle, Ms Sobol was forced from her taxi into a blue unmarked van, and whisked away.

Mr Navalny remains in detention along with the vast majority of other independent candidates.

Today’s demonstration was the fourth successive weekend that Moscow has protested.

On the one side were the protesters with their demands for free and fair elections. On the other side, the authorities who warned against a revolutionary scenario.

In the days leading up to the march, authorities tried several tools to minimise turnout. There were the warnings of violence and immediate arrest. Threats to round up young men dodging military service. And a music and food concert – though apparently organised without first securing the agreement of headliners.

On the day, much of central Moscow was on lockdown. Cafes and shops near the city’s Boulevard ring, the route of the march, were shuttered on the advice of authorities. Mobile internet was knocked out over much of the central district.

Helicopters circled the skies above; and thousands of uniformed officers, the streets below.

The arrests came as promised, but initially at a much lower level than a week ago. Police tactics seemed to concentrate on kettling protestors into blocks along the protest route.

More forceful arrests came later in the day. One man was arrested, upside down, complete with his bike. Other shocking footage showed masked riot police repeatedly striking two unarmed protesters. They had locked arms in non-violently resisting arrest.

Moscow protests: hundreds detained by riot police Show all 20 1 /20 Moscow protests: hundreds detained by riot police Moscow protests: hundreds detained by riot police Riot police officers detain a participant of an unsanctioned rally urging fair elections at Moscow's Pushkinskaya Square AFP/Getty Moscow protests: hundreds detained by riot police Opposition leader Lyubov Sobol was among the hundreds arrested amid new rallies AFP/Getty Moscow protests: hundreds detained by riot police The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections Reuters Moscow protests: hundreds detained by riot police Police officers detain a woman during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Police in Moscow have detained a leading opposition figure as she was heading to an unauthorized rally and march protesting the exclusion of independent and opposition candidates from the Moscow city council election. Lyubov Sobol, who is one of the aspirants rejected from the ballot, has been detained in central Moscow and taken away in a police van. Police have detained dozens of other demonstrators. (AP Photo/ Pavel Golovkin) Pavel Golovkin AP Moscow protests: hundreds detained by riot police Law enforcement officers detain a participant in a rally calling for opposition candidates to be registered for elections to Moscow City Duma, the capital's regional parliament, in Moscow, Russia August 3, 2019. REUTERS/Tatyana Makeyeva TATYANA MAKEYEVA Reuters Moscow protests: hundreds detained by riot police Police block a square during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Moscow police on Saturday detained nearly 90 people protesting the exclusion of some independent and opposition candidates from the city council ballot, a monitoring group said, a week after arresting nearly 1,400 at a similar protest. (AP Photo/Alexander Zemlianichenko) Alexander Zemlianichenko AP Moscow protests: hundreds detained by riot police Riot police officers detain a man during an unsanctioned rally urging fair elections in downtown Moscow on August 3, 2019. - The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections. (Photo by Alexander NEMENOV / AFP)ALEXANDER NEMENOV/AFP/Getty Images ALEXANDER NEMENOV AFP/Getty Moscow protests: hundreds detained by riot police epa07754982 Russian riot police carry a detained participant of the liberal opposition protest action in the center of Moscow, Russia, 03 August 2019. Liberal opposition called their supporters to continue their protest actions against rejecting their candidates for Moscow City Duma elections, which is scheuled for 08 September. Most of the candidates have been placed on administrative arrest before and during last week protest action where about 1,300 participants were detained. EPA/MAXIM SHIPENKOV MAXIM SHIPENKOV EPA Moscow protests: hundreds detained by riot police Police block a street during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Moscow police detained more than 300 people Saturday who are protesting the exclusion of some independent and opposition candidates from the city council ballot, a monitoring group said. (AP Photo/Pavel Golovkin) Pavel Golovkin AP Moscow protests: hundreds detained by riot police epa07754984 Russian riot police try to catch a participant of the liberal opposition protest action in the center of Moscow, Russia, 03 August 2019. Liberal opposition called their supporters to continue their protest actions against rejecting their candidates for Moscow City Duma elections, which is scheuled for 08 September. Most of the candidates have been placed on administrative arrest before and during last week protest action where about 1,300 participants were detained. EPA/MAXIM SHIPENKOV MAXIM SHIPENKOV EPA Moscow protests: hundreds detained by riot police Law enforcement officers detain a participant in a rally calling for opposition candidates to be registered for elections to Moscow City Duma, the capital's regional parliament, in Moscow, Russia August 3, 2019. REUTERS/Shamil Zhumatov SHAMIL ZHUMATOV Reuters Moscow protests: hundreds detained by riot police Riot police officers detain a man during an unsanctioned rally urging fair elections in downtown Moscow on August 3, 2019. - The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections. (Photo by Alexander NEMENOV / AFP)ALEXANDER NEMENOV/AFP/Getty Images ALEXANDER NEMENOV AFP/Getty Moscow protests: hundreds detained by riot police epa07754930 Russian riot police detain a female participant of the liberal opposition protest action in the center of Moscow, Russia, 03 August 2019. Liberal opposition called their supporters to continue their protest actions against rejecting their candidates for Moscow City Duma elections, which is scheuled for 08 September. Most of the candidates have been placed on administrative arrest before and during last week protest action where about 1,300 participants were detained. EPA/MAXIM SHIPENKOV MAXIM SHIPENKOV EPA Moscow protests: hundreds detained by riot police Police officers detain a protestor, during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Moscow police on Saturday detained nearly 200 people protesting the exclusion of some independent and opposition candidates from the city council ballot, a monitoring group said, a week after authorities arrested nearly 1,400 at a similar protest. (AP Photo/Alexander Zemlianichenko) Alexander Zemlianichenko AP Moscow protests: hundreds detained by riot police Servicemen of the Russian National Guard detain a man during an unsanctioned rally urging fair elections in downtown Moscow on August 3, 2019. - The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections. (Photo by Alexander NEMENOV / AFP)ALEXANDER NEMENOV/AFP/Getty Images ALEXANDER NEMENOV AFP/Getty Moscow protests: hundreds detained by riot police TOPSHOT - Riot police officers detain a journalist during an unsanctioned rally urging fair elections at Moscow's Pushkinskaya Square on August 3, 2019. - The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections. (Photo by Alexander NEMENOV / AFP)ALEXANDER NEMENOV/AFP/Getty Images ALEXANDER NEMENOV AFP/Getty Moscow protests: hundreds detained by riot police Police officers detain men during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Russian group says at least 600 people arrested at unsanctioned election protest in Moscow. (AP Photo/Alexander Zemlianichenko) Alexander Zemlianichenko AP Moscow protests: hundreds detained by riot police Police block a street during an unsanctioned rally in the center of Moscow, Russia, Saturday, Aug. 3, 2019. Russian group says at least 600 people arrested at unsanctioned election protest in Moscow. (AP Photo/Pavel Golovkin) Pavel Golovkin AP Moscow protests: hundreds detained by riot police Law enforcement officers detain a participant in a rally calling for opposition candidates to be registered for elections to Moscow City Duma, the capital's regional parliament, in Moscow, Russia August 3, 2019. REUTERS/Tatyana Makeyeva TATYANA MAKEYEVA Reuters Moscow protests: hundreds detained by riot police Riot police officers detain a man during an unsanctioned rally urging fair elections in downtown Moscow on August 3, 2019. - The rally is the latest in a series of demonstrations after officials refused to let popular opposition candidates run in next month's city parliament elections. (Photo by Vasily MAXIMOV / AFP)VASILY MAXIMOV/AFP/Getty Images VASILY MAXIMOV AFP/Getty

Speaking with The Independent a few minutes before her arrest, Ms Sobol said she anticipated it would only be a matter of time before she too was detained.

“I understand my stance will end in jail,” she said. “And I understand the consequences of my hunger strike.”

The opposition politician has lost over 8 kg since starting her protest last month. She was clearly weak when The Independent spoke with her, and required support to walk any serious distance.

But she said she was ready to go to the end, and claimed she would only stop when authorities opened up the elections to opposition candidates.

“I have exhausted every legal avenue,” she says. “I have chosen this radical route because Putin doesn’t like hunger strikes. We saw this with Oleh Sentsov,” she said, referring to the Ukrainian film director held in a Siberian prison on disputed terrorism charges.

Ms Sobol said she had not yet been arrested only on account of her five-year-old daughter.

Russian law forbids administrative arrest of anyone with dependent minors. At the time of her arrest, it seemed likely that Ms Sobol would instead be presented with criminal charges.

Five hours into the march, OVD-Info, the NGO watchdog that provides legal assistance to the arrested, reported that a total of 685 people had been taken into police custody. That number reached 828 by the end of the day, and is likely to rise further.

Most of the arrested were detained on Trubnaya, Pushkinskaya or Kropotkinskaya, three main squares along the route.

Igor Kalyapin, a prominent anti-torture activist and a member of Vladimir Putin’s official Council on Human Rights, was one of those taken away in a police van.

Working from a secret location in central Moscow, the OVD-Info volunteers told The Independent that the proportion of minors arrested looked like it was higher than at the last rally.

But their main worry concerned a change in the way prosecutors were handling the arrests.

For the first time since 2016, state investigators were being sent directly to police stations, said Grigory Durnovo, OVD-Info’s monitoring coordinator. That, he said, indicated that authorities planned to open criminal cases the same day.

“If they begin pre-trial interrogations, it will be impossible to get lawyers in,” he said.

As for Ms Sobol, it appears she was driven around the city for several hours while the protest was at its peak, surfacing only in the evening at a police station near Vnukovo airport in south-eastern Moscow. There, she was charged with repeated violations of protest law. Late on Saturday evening, a judge fined her a maximum 300,000 rubles (GBP 3800).

Ms Sobol predicted Moscow's political crisis would continue to grow.

"There is no prospect of Putin improving the situation," she told The Independent. "Putin knows what Russian society wants, but he is choosing to ignore it."