It is possible that when a car drove into Valeria Gontareva at a pedestrian crossing in Knightsbridge, central London, in late August it was merely an accident.

But soon after, while Gontareva was recovering in hospital, her son’s car was set on fire back home in Kyiv. A few days after that, her family home in the Ukrainian capital was also burned down. For Gontareva there is no doubt that the attacks are part of a disturbing pattern.

“It’s revenge,” she said, appearing for an interview in a wheelchair in the lobby of the luxury central London apartment block where she now lives.

Gontareva made a number of powerful enemies during her reform-minded stint as the head of Ukraine’s central bank. However, she blames the attacks on one person: Ihor Kolomoiskiy, a controversial oligarch from whose control Gontareva wrested the country’s largest bank, PrivatBank. He denies responsibility and his supporters have said she is using the London incident as part of a PR campaign.

Facebook Twitter Pinterest Ihor Kolomoiskiy. Photograph: Mykhaylo Markiv/EPA

Gontareva said she had been threatened, in a jokey fashion, by Kolomoiskiy throughout her tenure at the central bank, a job to which she was appointed in 2014 by the previous president, Petro Poroshenko.

“It’s always like a joke with him. He never sent me a message: ‘I will kill you now.’ But he was threatening me for five years,” she said.

She claimed the threats started a month after her nomination, when she was called to the office of the presidential administration by the chief of Poroshenko’s administration, who introduced her to Kolomoiskiy.

“The first thing he said to me was: ‘Valeria Alexeyevna, you are without any bodyguards. Do you know it only costs $10,000 to have someone killed in this country?’ I told him I had bodyguards, which was a lie. And he said: ‘Ah, with guards it will cost $100k.’”

The attacks on Gontareva have come as a campaign against her reforms is under way, and as Kolomoiskiy has returned to the country, seeking compensation over PrivatBank.

The case has become a major scandal in Ukraine. The national choir and a comedy troupe close to the president were rebuked last month for a skit mocking Gontareva and the arson attack on her home, prompting Ukraine’s culture minister to apologise on Facebook. And the conflict has also played a key role in stalled talks between Ukraine and the IMF for billions in future loans.

Facebook Twitter Pinterest Fire damage at Valeria Gontareva’s family home. Photograph: Ukrinform/Barcroft Media

It is a test for Ukraine’s new president, Volodymyr Zelenskiy, a political neophyte elected earlier this year after promising a new kind of politics. He is seen as close to Kolomoiskiy, after making his name as an actor in a show broadcast on the oligarch’s television channel.

Zelenskiy made headlines recently after Donald Trump dragged him into the 2020 election race by demanding an investigation into Joe Biden. But in the end, it may be how he navigates his relations with Kolomoiskiy, rather than with Trump, that comes to define his legacy.

During her time at the bank, Gontareva said she frequently received anonymous threats. At one point, a coffin was left outside the central bank with a Gontareva cut-out inside. A painting of a pig swathed in a Russian flag appeared on the wall of her home. In 2017, Gontareva decided she had had enough, and resigned. Her family had insisted she leave the bank in the face of repeated threats, she said.

Facebook Twitter Pinterest A burnt-out car reportedly owned by Gontareva’s son in Kyiv. Photograph: Valentyn Ogirenko/Reuters

Gontareva is widely credited with cleaning up the banking sector, including by nationalising PrivatBank, which has accused Kolomoiskiy and his associates of the misappropriation and laundering of proceeds of corporate loans issued by the bank while he owned it. He has dismissed the allegations as nonsense.

“It was a unique situation – 33% of the private individual deposits and 50% of transactions, and the business was in the hands of an aggressive oligarch,” said Gontareva. “It was just a Ponzi scheme.”

Since Zelenskiy’s election, Kolomoiskiy has returned to Ukraine, amid rumours he is seeking a financial settlement for the PrivatBank case, and international investors have been spooked by Zelenskiy appointing a number of Kolomoiskiy-linked figures to key posts, including making the oligarch’s former lawyer, Andriy Bohdan, his chief of staff.

Kolomoiskiy initially agreed to an interview with the Guardian but later stopped answering messages. However, those seen as allied to the oligarch have dismissed Gontareva’s claims of a campaign against her.

“They decided to use this accident to maintain a PR campaign that somebody is trying to threaten her,” said Alexander Dubinsky, who was elected to parliament as a member of Zelenskiy’s Servant of the People party earlier this year.

Facebook Twitter Pinterest Ukraine’s president, Volodymyr Zelenskiy. Photograph: Efrem Lukatsky/AP

Dubinsky previously worked as a journalist on the 1+1 channel partly owned by Kolomoiskiy, and has become one of the loudest critics of Gontareva and the National Bank, saying it preyed on banks and sold off their assets in corrupt auctions.

“You need to understand that millions of people were affected by her decisions to bankrupt banks, millions of people lost their money,” he said in an interview at a cafe in Kyiv’s fashionable Podil district.

Dubinsky said he did not believe there was any actual threat to Gontareva, despite the apparent car accident in London and the firebombing of her house, suggesting the attacks may have been faked.

Earlier this year, he urged his more than 130,000 Facebook followers to begin a letter-writing campaign to the London School of Economics, where Gontareva has been given a fellowship, accusing her of stealing state funds. He has also sought to open a parliamentary commission to investigate the National Bank, but has been blocked by members of his own party.

He denied his campaign against Gontareva was carried out on Kolomoiskiy’s orders, saying he did not have a business relationship with the oligarch and had not spoken with him since before Zelenskiy’s election.

Some diplomatic observers say the story is a typically murky Ukrainian tale with no obvious good guys, but others involved in the country say Gontareva’s role in cleaning up the banking sector should not be underestimated.

“People don’t realise what Ukraine avoided in 2014. Together with the IMF and foreign advisers, they cleaned up the banking sector, and her work was very important,” said Leszek Balcerowicz, who was responsible for reforming Poland’s economy in the 1990s and was brought into Ukraine in an advisory capacity by Poroshenko in 2016.

He said the nationalisation of PrivatBank had been due to an enormous hole in its budgets, and was fully justified. “In any normal country you would get arrested for what happened to PrivatBank before,” he said.

Gontareva said she had no plans to return to Ukraine in the near future, but hoped Zelenskiy had the character to stand up to Kolomoiskiy.

“I know that he was a puppet, but let’s hope that when you’re 40 years old, clever and handsome, you don’t want to be a puppet. For me it doesn’t matter who he was. It matters who he will be,” she said.