Alexander Lebedev in Russian TV fight Reuters

In his skinny jeans and basketball boots, he may appear to be the model of a modern media mogul. But Alexander Lebedev, the billionaire owner of the Independent and London Evening Standard, has shown a flash of his old KGB steel after punching a businessman in the face during a Russian television show.

Lebedev, 51, knocked Sergei Polonsky, a property developer, from his chair as both men were appearing as guests on a show about the global financial crisis that was being recorded in Moscow for the NTV channel on Friday.

The incident took place when Polonsky, a wealthy real estate developer, lambasted his fellow pundits and gestured at Lebedev saying: "I'm already worn out from the desire to give [him] a punch in the chops." In response, Lebedev said: "Well, try it" and sprang to his feet.

Lebedev was persuaded by the host to take his seat, but seconds later he swung from a sitting position and hit Polonsky with a right cross as the latter began criticising him again.

A second blow which did not connect cleanly sent the developer tumbling backwards in his chair to the floor.

The newspaper owner then advanced across the stage in a hunched, pugilist's pose and stopped in front of Polonsky, saying: "Go on then, or are you waiting for me to take off my glasses?"

There were gasps of shock and the host called security guards as the two faced off. A stricken-looking Polonsky, 38, the former owner of Mirax Group, a large developing company that went bankrupt earlier this year, did not respond for some moments before mumbling: "I'm in shock." Both men were persuaded to calm down.

Polonsky is well known for his brash statements, in particular saying in 2008 that anyone without a billion dollars is a "loser" and "those who don't have a billion, can go to hell".

During the recording of the NTV show he reportedly complained to Lebedev for drawing public attention to a crack in a skyscraper Polonsky was building in Moscow.

Both men commented on the confrontation on social media over the weekend. Polonsky posted a picture of a scratch on his arm and of the seat of his jeans with a tear in it. He said he had requested footage and would consider legal action against Lebedev.

"NTV has promised to give a full copy of the programme for a court action," Polonsky wrote on Twitter. "How disgusting and repulsive it all is."

Lebedev, who served as an officer in the KGB and Russia's foreign intelligence service, played down the incident in interviews with local media.

He told a news agency he had asked Polonsky to confirm whom he wanted to punch: "I said, 'Do you mean me?' He replied, yes. After which I neatly neutralised that absolutely unfounded threat."

Lebedev also said Polonsky had "behaved like a street hooligan", been rude to several guests and conducted himself with "real aggression" during the recording of the show.

"I grew up in Soviet Moscow and unfortunately, as a youth, took part in many such incidents," he wrote in his blog, saying that normally you do not get a warning when you're about to be hit.

"In a critical situation, you don't choose: I don't see any reason to get hit first if you know it's coming."

In a sharp aside, Lebedev added: "Now he's showing his ripped trousers, which is rather difficult to comment on. He got it in the face, but he holds up trousers with a hole in the backside. Strange."

Lebedev joined the KGB in the early 1980s and trained at its spy school, the Red Banner Institute, where he most likely received instruction in hand-to-hand combat.

He transferred to London in 1987 and worked there as a foreign intelligence officer until 1992.

He is a keen sportsman and swims or pumps iron every day in one of several gyms at his home and offices.

The two men received expressions of support online, with Lebedev appearing to gain the most.

Dmitri Rogozin, Russia's representative to Nato, tweeted: "Nice one, Lebedev, although fighting is not good. He deserved it. You're a real man."

Expert view

A sneaky, bar-room blow

When Alexander Lebedev said he "neutralised" a man by punching him in the face on Russian television, he echoed the dark argot of the KGB, the agency of which he was a member long before spending a slice of his fortune on the Independent and the Evening Standard.

As for the aesthetics of his execution, the 51-year-old banking and media billionaire may not be ready for his undercard debut in Las Vegas just yet. Whatever he learned about martial arts in his days as an agent would seem to be distant memories.

He owed some of his success to the fact that his antagonist, Sergei Polonsky, took the blows while perched on a chair at the back of a podium, and tumbled over on to the floor, embarrassed rather than hurt. It was in the fine tradition of sneaky punches in bar-room brawls.

Having signalled his displeasure by standing over Polonsky in a macho manner, he flexed his neck muscles à la Mike Tyson, sat down and, with all the speed expected of a middle-aged businessman, rose again to land a right cross of moderate force, then missed with a follow-up left in a tangled ending to their little spat.

Next time he bumps into John Prescott while roaming Westminster's corridors of power, he might take a few tips from the former seaman who famously dealt a pesky egg-lobber on the 2001 general election campaign trail a neat jab conjured up from his days as an amateur boxer.

Lebedev did observe one diktat of the fistic arts: be first … and second, if you can.

Kevin Mitchell, Guardian boxing correspondent