A protester who disrupted the National Conservatism Conference with a speech about fascism says he was let in to the exclusive event because he was “an elderly white man without a social media presence”.

Prog rock musician Dirk Campbell, 72, blagged his way into the conference that had barred a number of left-leaning publications, including openDemocracy, Byline Times and Novara Media.

Asked on the application form for his social media profiles, Campbell told the administrators he was a “techno-klutz” and listed only a website linked to his business as a composer, which contained “nothing contentious”.

By contrast, openDemocracy and others were told weeks ago that there was no space for them at the right-wing gathering where a number of ministers and MPs were due to speak.

After gaining entry, Campbell interrupted Jacob Rees-Mogg’s opening speech by telling the audience he wanted to speak to them about the characteristics of fascism.

Campbell told openDemocracy he had taken to the stage to “draw attention to the fact that National Conservatism is the first step on the road towards fascism”.

Going on to say that those at the conference were “romanticising the [idea of the] nation, which is a core definition of fascism” he added that he was “really staggered” by the fact that the second speaker was “talking up all the glories of the British empire, British history and culture” while “completely ignoring all the crimes that were committed by the British empire”.

“The British empire screwed over all of its colonies, suppressed the people, extracted their resources [and is] still oppressing them financially,” he said.

This romanticisation of Britishness has been identified as a feature of far-right groups in the UK. Patriotic Alternative, Britain First and the English Democrats party all have policies that rely upon the image of the UK as an idyllic nation state that must be protected at all costs.

Home secretary Suella Braverman has been accused of nodding to other far-right talking points via her comments about immigration and her claim that policing has become too “woke” to clash with protesters. Other confirmed speakers have faced questions over their own apparent links to the far-right, including MP Lee Anderson, who was revealed earlier this year to be connected to a scooter club whose members include known neo-Nazis. Anderson has denied he supports far-right groups.

Campbell was led away by security, who forgot to remove his wristband – meaning he was able to return to hear Rees-Mogg saying that, in Campbell’s words, “we do advocate for free speech, apart from that interruption earlier, which was a bit annoying”.

Climate activist group Extinction Rebellion (XR) has claimed Campbell as one of its ‘disruptors’, but he told openDemocracy that neither he nor the other two protesters who interrupted proceedings were specifically representing the movement.

Instead, he said, they were there to “make the point that… Suella Braverman and the public order act [were part of an] intensification of the police right to clamp down on protest, [which is the] thin end of the wedge of fascism”.

This clampdown was seen in action last week at the King’s coronation, where a number of protesters were arrested and held for more than 18 hours before being released without charge following a social media outcry.

Campbell said the audience appeared to contain a broad mix of people, with a lot of students present. Costs for the event ranged from £50 for a student ticket to “Beaconsfield Circle” tickets, which include a table and cost £20,000. Campbell said he only saw one man sitting alone at such a table, but did not recognise him.

He added that the political stance of speakers at the conference was “anti-democratic and populist in a bad ‘Make Britain Great Again’ way, which is very divisive and polarising”. The conference was “appealing to the worst aspects of xenophobia and tribalism,” he said.

The conference continues until Wednesday.