Whatever adjectival qualifier they use, everyone in Kiev is sure they have witnessed a revolution: electoral, populist, socialist, libertarian or, in the opinion of the more excitable, Bolshevik.

Never before has the country switched to the command of one person. Not even Viktor Yanukovych, the disgraced former president who tried to build a dictatorship before being overthrown, managed it. Mr Yanukovych had 72 deputies. Volodymyr Zelensky, a 73-per-cent man of the people, is the pied piper of a record-breaking 254 deputies, plucked from the nation.

Mr Zelensky and his Servant of the People party have promised to make their revolution a “nice” one.

The Servants – all of them new to frontline politics – say they will reset the country from the scourge of corruption. Boost incomes for the second-poorest nation of Europe. Introduce a more honest kind of politics.

But critics point to the team’s inexperience, and an approach to political enemies that, they say, is not entirely out of sync with 1917.

Ukraine Elections 2019 in pictures Show all 26 1 /26 Ukraine Elections 2019 in pictures Ukraine Elections 2019 in pictures Volodymyr Zelenskiy, centre right, and his wife Olena Zelenska, greet supporters after exit polling gave the comedian a commanding lead AP Ukraine Elections 2019 in pictures Outgoing Ukrainian President Petro Poroshenko raises his hand with his wife Maryna at his party headquarters in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures Ukrainian presidential candidate Volodymyr Zelenskiy reacts following the announcement of the first exit poll REUTERS Ukraine Elections 2019 in pictures Comedian and leading Ukrainian presidential candidate Volodymyr Zelenskiy plays ping pong with a journalist at his election night gathering in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21 Getty Ukraine Elections 2019 in pictures Election officials count ballots at a polling station in Kiev during the first round of Ukraine's presidential election, AFP/Getty Ukraine Elections 2019 in pictures People walk in front of St. Sophia Cathedral in Kiev during Ukraine's presidential election AFP/Getty Ukraine Elections 2019 in pictures Ukrainian servicemen sit in a truck to head to a polling station, near the front line with pro-Russian separatists, near Butivka, Donetsk region AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishke AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures Ukrainian citizens living in Kyrgyzstan vote in Ukraine's presidential election at a polling station in the Ukrainian embassy in Bishkek AFP/Getty Ukraine Elections 2019 in pictures A young girl casts the ballot of a man at a polling station in Kiev on the first round of Ukraine's presidential election, on. Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 2 AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky waves in front of voting booths at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Former Ukrainian Prime Minister and presidential candidate Yulia Tymoshenko speaks with the media after casting her ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky casts his ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky gestures in front of voting booths at a polling station during Ukraine's presidential election in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures Ukrainian comic actor, showman and presidential candidate Volodymyr Zelensky walks with his ballot at a polling station during Ukraine's presidential election in Kiev AFP/Getty Images Ukraine Elections 2019 in pictures A view of the building of the Ukrainian Central Election Commission in Kiev during Ukraine's presidential election. AFP/Getty Ukraine Elections 2019 in pictures Ukrainian President Petro Poroshenko (L) casts his ballot at a polling station in Kiev on the first round of Ukraine's presidential election, The 53-year-old president has positioned himself during the political campaign as the only person able to stand up to the Kremlin and has promised to return Crimea to Ukraine if he is re-elected. AFP/Getty Ukraine Elections 2019 in pictures A voter emerges from the voting booth after filling out her ballot for Ukraine's presidential election in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21. Getty Ukraine Elections 2019 in pictures Ukrainian president Petro O. Poroshenko (C), running for re-election, receives his ballot in Ukraine's presidential election on in Kiev, Ukraine. If no candidate receives more than 50% of the vote, the top two vote-getters will face off in a second-round election on April 21 Getty Ukraine Elections 2019 in pictures A woman holds her ballot as she leaves a voting booth at a polling station in Kiev on the first round of Ukraine's presidential election. - Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 21 AFP/Getty Ukraine Elections 2019 in pictures A young girl casts the ballot of a man at a polling station in Kiev on the first round of Ukraine's presidential election. Exit polls are expected when voting stations close at 8 pm local time (1700 GMT). First preliminary results are expected several hours after. Barring a shock result in which one candidate crosses the 50 percent threshold in the first round, a run-off will be held on April 21 AFP/Getty Ukraine Elections 2019 in pictures Ukrainian servicemen queue to cast their ballots at a polling station near the front line line with pro-Russian separatists near Avdiivka, Donetsk region, during the first round of Ukraine's presidential election AFP/Getty

As the Servants celebrate their victory, Ukraine’s former leaders are certainly getting used to very different lives.

If Mr Zelensky’s team carries through a key pre-election pledge to expand lustration laws, all former MPs will be barred from public office.

Vitali Klitschko, a former boxer, ally of Zelensky’s predecessor Petro Poroshenko, and Mayor of Kiev, is engaged in a battle for his political life. He seems likely to lose control over local government to one of Mr Zelensky’s men. The battle took a dramatic turn last week with Andriy Bohdan, Zelensky’s pugnacious chief of staff, accusing Mr Klitschko of offering a bribe to keep in his job. The mayor shot back with a request to to the National Anti-Corrution Bureau to investigate Mr Bohdan's own history.

Kiev’s mayor, Vitali Klitschko, an ally of outgoing president Petro Poroshenko, is in a fight for his political life (EPA)

But most striking of all, Poroshenko, Ukraine’s fifth president, is being forced to give evidence in a dozen cases brought against him over alleged abuses of power.

The accusations cover the whole range – from alleged tax evasion in the sale of a shipbuilding yard to alleged treason over the sea clashes with Russia in November, which were followed with an attempt impose full-scale martial law.

There is no love lost between the Zelensky camp and Mr Poroshenko. They fought a bitter presidential campaign. The new administration does not hide its anger at the outgoing leader’s attempt to portray Mr Zelensky as a Kremlin and oligarchic stooge.

Officially, Mr Zelensky’s office plays no part in the criminal investigations. The prosecutions are mostly being pushed by Andriy Portnov, a powerful lawyer and a former deputy head of the Yanukovych administration. But there are enough informal links – Mr Portnov is close to Andriy Bohdan, and described in some quarters as his teacher – to raise suspicions.

Many believe the new administration will be unable to resist public demand for a conviction.

“Europe may squeal at the prospect of prosecuting a political opponent, but I think Zelensky is minded to go for it,” says Valery Kalnysh, the host of one of Ukraine’s most influential political radio shows. “There are three reasons why it makes sense for him: first, Poroshenko got filthy rich during his presidency; second, state investigators are no longer scared to probe; and third, a moment of personal revenge.”

Mr Portnov’s name comes up in any discussion about that third factor. The lawyer was pushed out of Ukraine by Mr Poroshenko’s post-revolution leadership in 2014, returning to Kiev only on the eve of Mr Zelensky’s victory. Now he has made it his business to feed requests to prosecute the former president to the State Bureau of Investigations.

Mr Poroshenko accuses the lawyer of pushing the interests of ex-president Yanukovych. Mr Portnov, in turn, makes no secret of the animosity he feels for Mr Poroshenko.

“I want to remove these people from the face of the earth,” he tells The Independent in Kiev. “Poroshenko is a criminal who in five years has sent our country back decades. I have the evidence for this and I intend to prove it.”

The words come out of Mr Portnov’s mouth like daggers, and they barely hide the anger lurking underneath.

‘Write that revenge was bleeding from my eyes if you like’: lawyer Andriy Portnov is pushing for the public prosecution of Petro Poroshenko (Oliver Carroll)

“You’re calling it revenge?” He says. “Well that’s your interpretation. Write that revenge was bleeding from my eyes if you like. I’d prefer to describe it as restoring justice and fulfilling a promise.”

On the crucial question, the crusading lawyer denies any working links with the new administration. “If they were helping me,” he says, “Poroshenko would already be in jail.”

Halyna Yanchenko, an anti-corruption expert turned high ranking member of Mr Zelensky’s new party, also rejected the accusation Mr Poroshenko was being pursued because of politics. There was no order to “go after Poroshenko,” she said, adding that that “wasn’t the way the new administration saw the world”.

What that did not mean is that Mr Poroshenko should avoid prosecution. “If there is a crime, he should be made to answer for it,” Yanchenko said. “But it’s a matter for law enforcement and not politicians to comment on.”

Members of Poroshenko’s administration are unconvinced.

The new, young team are falling into old traps of Ukrainian politics .... Ignoring procedure and law is a dangerous path, a slow-ticking bomb Ivanna Klympush-Tsintsadze, outgoing deputy prime minister

Ivanna Klympush-Tsintsadze, Ukraine’s outgoing deputy prime minister, told The Independent that the current course "looked like political persecution” – and not only against a political opponent but against an entire political force. The pre-election proposal to expand lustration to former deputies was a “route to dictatorship,” and "a disgraceful way to treat people who gave five years of their life when the country was on its knees."

“The new, young team are falling into old traps of Ukrainian politics,” she said. What was good was that the elections were free and competitive, but that process had resulted in an “unprecedented situation of one-party control.”

“There is a temptation to move away from formal procedure, to ignore procedure and law,” she said. “That is a dangerous path, a slow-ticking bomb.”

Some commentators play down the fears of a purge of the former elite.

Oleksandr Martynenko, head of the Interfax Ukraine news agency and a former press secretary to Ukraine’s second president, Leonid Kuchma, told The Independent that the promises of lustration already looked to be on the scrap heap. They were made in the heat of an election system, he said; the Zelensky administration is “looking for ways to step back.”

In Mr Marynenko’s view, the criminal cases against Poroshenko looked more like “an attempt to play on the former president’s nerves.”

The legal opinion on the prospects for Portnov’s prosecutions is split. The prosecuting lawyer Yevgeniya Zakrevskaya said there was no public evidence that looked like it might result in a criminal sentence. Instead, she suggested, the cases against Poroshenko looked like “a PR and information gathering exercise” for the wily Portnov.

But others are not so sure.

With decisions on the State Investigations Bureau being decided upon by criminal courts in Kiev, the criminologist Anna Maliar says the former president will end up having to rely on the justice system he left behind.

Unfortunately, this is the same justice system he only “pretended to reform,” she tells The Independent, "the very courts he used to settle political scores.”