Activists crashed former HMRC boss David Hartnett's party last Thursday - to present him with a lifetime achievement award for services to corporate tax avoidance (also known as a golden handshake).
The group, who call themselves 'The Intruders', posed as representatives from Vodafone and Goldman Sachs.
They were soon ejected from the dinner in Magdalen College, Oxford and told: “This is an unlawful conspiracy to trespass. You will depart immediately before we set the dogs on you.”
Retired Harnett presided over HMRC when they were accused of cutting "sweetheart" tax deals. Last year the influential Public Accounts Committee accused them of giving "cosy", preferential treatment to larger companies while putting public money at risk.
Harnett was accused by the committee of failing to collect £10m interest on a tax bill from Goldman Sachs.
At the time HMRC rejected the committe's conclusions, saying their report was based on "partial information, inaccurate opinion and some misunderstanding of facts".
Stephen Reid, 26, one of the activists in the video, told The Huffington Post UK they weren't scared when crashing the 'do.
"We were genuinely outraged and people should be generally outraged that this guy was speaking in this situation," Reid, who has links to UKUncut, told The Huffington Post UK.
"We've only done this one thing. And we haven't got any firm plans to do anything more. But it's obviously worked really well, and there's conferences and dinners like this all the time."