The Russian billionaire owner of The Independent and the London Evening Standard has said he has no regrets about punching a fellow businessman during a televised debate, even though prosecutors have launched a criminal investigation over the brawl.

Alexander Lebedev, whose wealth is estimated at £1.3 billion, said that “anyone in my shoes would have done the same”. He was referring to the moment when he attacked Sergei Polonsky, a brash property developer, who told him during a Russian television show about the global financial crisis that he would like to “punch someone’s lights out”.

In what he has since suggested was a pre-emptive strike, Lebedev hit Polonsky with two swift right hooks to the head, knocking him backwards off the studio podium.

“I don’t regret hitting him,” said Lebedev last week. “As far as I’m concerned, I had to act as he’d been aggressive throughout the show and had made threats. Anyone in my position would have done the same — in fact, I showed restraint.

“The only thing I regret is that people might now perceive me as a violent person, which I am absolutely not. Mostly, however, I’ve been inundated with messages of support.”

Since the confrontation Polonsky, who before his business went bankrupt last year once said that “anyone without a billion dollars should f*** off”, has filed a request for a criminal case to be opened against Lebedev on charges of hooliganism.

Prosecutors announced last week that they had launched a case in response to the complaint. If he is convicted of hooliganism, Lebedev, 51, a former KGB officer, could be fined the equivalent of £6,000, given 180 days’ community service or, in the worst case, be sentenced to up to five years’ imprisonment.

In a move that has attracted some derision, Polonsky’s complaint claimed, in a reference to Lebedev’s training in the KGB in the early 1980s, that he possessed “the fighting techniques of attack and defence”, which amounted to “the use of weapons”.

The complaint also suggested that Lebedev’s assault could have put Polonsky’s life in danger.

After the attack Polonsky posted photographs of his ripped jeans on the internet and later challenged Lebedev to a Twitter battle — with the loser obliged to leave Russia.

In a sign that he is taking the case seriously, Lebedev said last week that he had hired Genri Reznik, one of Russia’s leading defence lawyers, and dismissed the charges as nonsense.

“This case is rubbish,” he said. “Legally it doesn’t have a leg to stand on. I’ve instructed my lawyers to formally ask prosecutors to provide us with more details of the charges.”

Vladimir Putin, the Russian prime minister, has mocked the brawl and described it as hooliganism.

Lebedev, who presents himself a thorn in the side of the government, has come under pressure from Russian law enforcement agencies in the past year in what he has described as a campaign to force him out of Russia and strip him of his businesses.

Almost a year ago the offices of his National Reserve Bank in Moscow were raided by 30 armed police officers wearing masks who confiscated a number ofbank records.

The maverick tycoon has claimed that the raid was orchestrated by a gang of corrupt law enforcement officers from the interior ministry and the FSB — the successor to the KGB — who are seeking to strip him of his bank’s assets, valued at around £600m.

He said last week that “for now at least” he did not think the criminal case over the brawl with Polonsky was politically motivated. He also sought to play down the incident by recalling how, as a young man growing up in Moscow in the Soviet era, he had been involved in numerous street fights.

“That’s when I learnt to defend myself,” he said. “Moscow was full of hooligans and drunkards looking for trouble.”

Lebedev did not always come out on top, however. “I was hospitalised more than once after a street fight,” he said. “Twice I broke my foot and once my arm. On one occasion I was so badly bruised I couldn’t recognise myself in the mirror. My face looked like a mask.”