Yevgeny Chichvarkin, a former mobile phone tycoon, has lived in the UK for almost a decade, after fleeing Russia in 2009, and has become an active anti-Putin campaigner. He had never considered hiring private security guards, but the opening of a murder investigation into the death of fellow exiled Russian businessman Nikolai Glushkov has prompted him to reassess how much danger he might be facing.

“We’ve been discussing it. If you do it, you have to have it 24/7, for everyone. It costs really big money to do it properly,” Chichvarkin said. “For the moment we haven’t decided.” He knew Glushkov a little and was shaken by his death. He assumes he will be on the list of Russian exiles the Metropolitan police are beginning to contact to talk to about security, but has yet to hear from anyone.

Chichvarkin combines running a Mayfair wine business, Hedonism, with anti-Putin campaigns for the Russian expatriate community. On Sunday, he organised a protest outside the Russian embassy in central London, where Russians were queueing to vote in the presidential election.

He suspects his political activity has attracted the interest of the FSB, Russia’s security agency, and is increasingly uneasy about his personal safety. He is particularly concerned about how office laptops have been going missing in odd circumstances. Two weeks ago, his assistant had her laptop stolen from her bag in Soho. It was the computer he had been using to send donations via PayPal to the Russian opposition politician Alexei Navalny. Chichvarkin thinks he has sent about £100,000 in small amounts to support Navalny’s political fund; Navalny is barred from standing in the presidential election following a fraud conviction that many believe was trumped up to prevent him from mounting an electoral challenge to Putin.

Twice when his assistants have travelled back to London from Russia in recent months, they have found that that their suitcases have been lost in transit, then recovered by the airline 24 hours later. When they were finally delivered, there were indications that the bags had been searched and the laptops inside tampered with.

He thinks there have been six separate incidents where assistants’ laptops have been searched or stolen over the past few years. Chichvarkin’s car has been opened, and contents from inside strewn around the street. He has reported each incident to the police, who he felt did not show huge interest in investigating: “The police don’t take it seriously unless someone is dead.”

Yevgeny Chichvarkin: ‘I can’t be 100% relaxed – there is always an element of risk.’ Photograph: Teri Pengilley/The Guardian

Chichvarkin, who co-founded Evroset, a chain of 5,000 mobile phone stores, lost much of his fortune when he was obliged to flee Moscow hiding in the back of a taxi in 2009. He claimed he was forced out by demands from corrupt officials to pay bribes; he was later accused by Putin’s officials of kidnapping.

His campaign material for Sunday’s protest described Putin as a “threat to peace and democracy outside Russia” and dismissed the election as a “sham”, with all opponents and independent media comprehensively silenced. He and fellow protesters were calling on Russians on Sunday not to vote, because in the absence of any credible opposition, they argue that any vote is a vote for Putin. Like many Russians who oppose Putin, his picture on social media carries the slogan: “I’m not voting”.

Until now he had made the decision not to be consumed by fears for his personal safety. “It is impossible to live when you are always worried,” he said. “Of course I feel a bit less safe now, but I don’t see any strong reason why I would be killed.”.

He finds it hard to shrug off concerns entirely, because he knows how unpredictable the Kremlin can be. “The problem is that these are FSB people, and they are different from normal people and we don’t know how their brains operate. I can’t be 100% relaxed – there is always an element of risk.”

Most Russians in London have not bothered with hiring security guards until now, he said. “The risk here is much lower than it would be in Russia. But I worry for the people who work for me and for my family.”

He has no expectation that the expulsion of 23 Russian diplomats from London will mean the peculiar laptop disappearances will stop. “Someone told me there are 300 FSB agents in the UK. I don’t know if that’s the right figure, but if 23 are kicked out then 277 are still here,” he said. “Every other person in the Russian embassy works for the FSB. It will make no difference.”

Aside from concerns about his safety, it is an unsettling time to be a Russian exile in the UK. In the past fortnight, Chichvarkin has been dismayed to find that his neighbours in Chelsea have become very nervous about living near to him. They have become unwilling to drop by and have stopped supporting his campaign to improve the children’s playground in the small square outside their street. His nanny told him there have been mutterings about the expensive sand he had delivered for the local children to play in.

He is annoyed by the mounting anti-Russian hostility. “I’ve been here for nine and a half years. I’ve created jobs where people are paid wages three or four times higher than market level, the company has created millions in taxes every year for the UK government, and now my neighbours don’t want to sign the playground petition. It’s crazy.”