The Guardian’s revelation that Facebook campaigns which appear to be spontaneous outpourings of popular sentiment are actually run by employees of a firm run by the Australian lobbyist Lynton Crosby comes at a dangerous moment for democracy in Britain. Local elections are certain to happen next month; European elections may well be coming; and beyond all these looms the possibility of a general election in the next six months. Social media will play a role in all these campaigns, as they did in the referendum.

We cannot know to what degree the breach of campaign funding laws by Vote Leave, the official and supposedly respectable wing of the leave campaign, changed the outcome of the 2016 referendum. But we do know that its punishment – a £60,000 fine imposed by the Electoral Commission – was minimal. The lesson for any political operative is clear.

This is a problem distinct from other difficulties posed by extremist content and “fake news”. All campaigns in any medium will involve misrepresentations, but there are two aspects specific to social media. The first is that advertisements can appear in people’s feeds with no indication of who is behind them; even when a name is attached, there is little way for the general public to know anything more about the person nominally responsible. The second is that they can be so precisely targeted that nothing in them is ever opened up for public debate and refutation.

Since these problems were first raised in the aftermath of the referendum, Facebook has responded to pressure in some helpful ways. Political adverts are held in a public archive, and the tools the company provided made it possible for the Guardian to expose the role played by the staff of Sir Lynton’s organisation in the most recent campaigns. The concept of “coordinated inauthentic behaviour”, which the company invented to deal with the problem of foreign troll farms, could usefully be applied to domestic actors too.

But the problem cannot be left to the tech companies to solve. Journalism plays an important part, but so must public regulation. The Electoral Commission is not the only watchdog whose bark is muffled and whose bite is more gummy than toothful. The whole of the organisational apparatus which is meant to guarantee that elections are openly and fairly contested in Britain turns out to be inadequate to deal with the challenge posed by campaigning on social media, as a parliamentary committee recently noted. The system was set up to deal with analogue campaigning by identifiable political parties and their candidates. Now we operate in a digital world where parties are partially replaced by overlapping pressure groups whose aims and funding are opaque.

British politics is already too much influenced by such groups working on politicians. We are dangerously unprepared for a world in which they can speak directly to the voters too.