We’ve come to expect strange things from coalition government, but the events of the last few days have been particularly odd. On Saturday, several newspapers contacted the Department of Education about a story claiming that its budget was in chaos. Officials set about drafting a clear rebuttal. But this was vetoed by David Laws, the Liberal Democrat schools minister, preventing his department from denying a damaging story.

This act of self-harm was just the latest twist in the spat between the Liberal Democrats and Michael Gove’s former adviser, Dominic Cummings. Following Cummings’s revelations about the shambolic state of the Liberal Democrat programme to give every five- and six-year-old a free school meal, the Lib Dems responded by briefing that the rest of the Education budget was being raided to bail out Gove’s free schools project. It makes one wonder what state the coalition will be in by the time its gets to March next year.

The past few weeks have been dire for coalition comity. Senior Liberal Democrats are still smarting over a Cabinet home affairs committee meeting in which they felt that the Tories tried to steamroller Clegg on the issue of knife crime. The Lib Dems accuse the Tories of caucusing beforehand to agree a joint line, mobbing Clegg in the meeting, and then leaking Cabinet correspondence when they didn’t get their way.

These Tory tactics were, in fact, the highest form of flattery: an imitation of the approach the Liberal Democrats have used at various times in the coalition. But things are more tense inside government than they have been for a while, hence the furious reaction.

Those close to Clegg are aware that the days after the European and local elections promise to be the most testing for him since the loss of the referendum on the alternative vote in 2011. The pain will be drawn-out. First will come the council results on Thursday and Friday, which will probably be bad news for Clegg. Then, on Sunday, they’ll learn the European results. These will show just how far Lib Dem support has fallen. Even in the most optimistic scenario, the party will lose more than two-thirds of its MEPs.

In the aftermath of the elections, there’ll be calls for the Lib Dems to quit the coalition early — a move that Clegg implacably opposes. He feels that staying in office until the end is essential to show that coalitions can work and that the Liberal Democrats are a party of government. Those close to him also ask why the Liberal Democrats should walk out now with the economy recovering.

The Tory leadership, too, is keen for the coalition to go the distance. It fears having to run a minority government and believes that the stability coalition provides outweighs its downsides. Cameron also wants to keep his post-election options open. When it was reported that he would rule out a second coalition in his 2015 campaign, Cameron personally reassured Clegg that this wasn’t the case.

Unlike in 2011, though, Clegg will not be able to rely on Cameron’s aid to get him safely through the next few months. With less than a year to the general election, the Tory leader is not in a position to help his coalition partner. There’ll be no string of policy concessions to the Deputy Prime Minister.

Clegg’s team has, so far, taken sensible precautions against a leadership challenge. They put Tim Farron, the party president and the strongest left-wing candidate, in charge of the European election campaign. And Vince Cable, the minister most likely to be touted as Clegg’s replacement, will be in China as the results come in.

Clegg, meanwhile, has made it clear that he won’t go without a fight. His confidants have let it be known that if he were deposed, his loyal lieutenant Danny Alexander would be a candidate in the election that followed. These moves are likely to prove effective. As Gordon Brown showed five years ago, if your party knows that there can be no smooth transition and that the leadership can’t be changed without a long and bloody struggle, it will stick with the incumbent.

But Clegg will be more vulnerable than he has been for some time — one person hoping so is Cummings. Since leaving government earlier this year, Cummings has become a one-stop anti-Clegg shop for the media. At first the Lib Dems believed that they could persuade the Tories to call him off. But they now accept that Cummings is beyond Downing Street’s and, even Gove’s, control.

At first glance, Cummings has the CV of a political insider. He went to Oxford and has worked in or around politics for more than a decade. But he isn’t a Westminster creature. After Oxford, he worked in Russia; after fighting the euro, he left London again. He has no desire for political preferment and his career has been built on understanding how much voters dislike politicians. When he ran Business for Sterling, the pressure group that helped keep Britain out of the euro, he kept Tory MPs away from the campaign. In 2004, he ran the campaign that comfortably defeated Labour’s plans for a North East assembly by arguing that the last thing the region needed was more politicians.

Cummings is determined to expose the worst aspects of coalition horse-trading because he hopes to change how the Conservative party works after the election. He wants the public to know how their money is used to provide quick newspaper headlines. He couches all his attacks in the language of anti-politics, complaining about ‘Clegg blowing taxpayers’ money on vanity projects’, and repeatedly accusing the Deputy Prime Minister of being a liar. It is crude but effective. Indeed, part of the reason it is working is that Clegg keeps responding. If he simply ignored the assaults, they wouldn’t have attracted so much attention. Instead, Clegg is using his election campaign interviews to denounce Cummings as ‘loopy’, thus ensuring continued media interest in the story.

Part of the problem for Clegg is that Cummings has picked on a policy where it will be obvious if the rhetoric doesn’t meet reality: pupils will either get their free lunches or not. It is hard, though, to see how this policy can be implemented smoothly when the Department for Education still doesn’t know which primary schools currently have kitchens and which don’t. But what should worry the Liberal Democrats most is what this constant infighting between the two parties will do to the public’s appetite for another coalition.​