"An organiser of the London march, Keiran MacDermott, said protesters hoped to stop the government from triggering Article 50, which begins the formal process of the UK's withdrawal from the EU."That is essentially an admission that the protest is against democracy and representative government because it is only be enacting Article 50 of the Lisbon Treaty that the government can actually represent the 52% of people who voted for Britain to leave the E.U. An important implication to be drawn from this is that those protesting are, in effect, advocating the electoral disenfranchisement of all the other people who disagreed with them.
The argument cited repeatedly in that BBC report is that the Leave campaign "lied" and therefore the result of the referendum should be ignored by the government. Aside from whether that claim is correct or not, the conclusion presupposes the insufferably arrogant presumption that the people who voted leave were incapable of judgement. It also conveniently ignores similarly questionable claims from the Remain campaign about Brexit being a "catastrophe". But a catastrophe for whom? Just as those protesting against democracy now in London accuse Leave voters of being misinformed, others could turn around and accuse Remain voters of having been misinformed.
So that argument is not about facts but about the spiteful and arrogant presumptions which one side has about the other. There is also the claim that, because Leave voters were generally older than Remain voters, this means that the old have "stolen" the future of the young. There is a dark, if only slight insinuation there that there ought to be age restrictions on adults who would like to vote. Again, the implication to be drawn here is that the protesters are effectively calling for the electoral disenfranchisement of the people who disagreed with them.
Am I really being hyperbolic when I characterize these people as a "progressive despot class"? The sooner their parasitical supporting structures can be taken away from them the better.