Alastair Campbell has been captured on camera in an altercation with a 61-year-old man in Hampstead.

Tony Blair and Alastair Campbell (right) at a lobby briefing in 2000 (BBC)

CCTV footage of the incident was obtained by the Ham&High after the man, who claims he was involved in the spat last Monday, contacted Bradford West MP George Galloway.

UK Respect party leader then tweeted to his 230,000 followers that he would be investigating his claims, and “exclusively revealing” his findings on Twitter:

The video, shot in Perrin’s Lane shortly after 1.15pm, shows Tony Blair’s former spin doctor walking towards Hampstead High Street clad in running gear.

Campbell is confronted by the man, and appears to hit the man on his shoulder. The 61-year-old then goes after Campbell and the altercation continues out of shot.

He claims the man then spat at him, with “most of the spit landing on my shirt, some on my face”. Campbell also alleges he was kicked in the leg.

“Though I am used to robust debate, this is the first time I have been attacked in a public place and the first time I have been spat at.

“We have lived in Gospel Oak, happily and as active members of the local community, for decades and it has always felt safe and friendly.”

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“I was walking up Perrin’s Lane and I saw Campbell coming towards me and I made a remark,” the man, who wished to remain anonymous, told the local paper. “As he came past me, I said, ‘The biggest piece of **** I’ve ever seen in this street.’

“He then struck out and hit me on my left shoulder. I turned to confront him and said, ‘That is assault, you should be in prison, not running around the streets of London.’

“At which point spitting ensued and then I aimed a blow with my foot that did not connect. Nothing that I did was illegal and he had no right to punch me.”

Campbell denies spitting at the man. Both men reportedly agree that the CCTV footage verified their individual accounts of the incident.

The former director of communications has since responded to the report with a detailed blog post on his website which includes his full statement about the incident.