The one thing plotters hate more than coalition is the PM

Inside Westminster: Cameron lacks the authority that an outright win in 2010 would have given him

Just when David Cameron should have won lots of friends among Conservative MPs, he finds himself with more enemies. For years, many Tories have craved an in/out referendum on Europe. How did they show their gratitude after he announced one 10 days ago? Apparently by launching a backbench plot to topple him as party leader. Mad world, politics.

The “ABC” plot – Anyone But Cameron – is viewed with an understandable sense of irony in Downing Street. “He could part the Red Sea and it would still not be enough,” said one loyalist. One lesson is that the Eurosceptics are never satisfied. The ‘Great Speech on Europe’ has not bought the Prime Minister time, as he had hoped. A head of steam is already building on the Tory backbenches for legislation before the 2015 election to guarantee a referendum after it.

Why the plotting now? Many Tories can’t forgive Mr Cameron for not winning an overall majority against Gordon Brown in 2010. They hate the Coalition, and were dealt a painful reminder of their party’s predicament this week when the Liberal Democrats voted with Labour to extinguish any flickering hope that new parliamentary boundaries handing the Tories a net 20 seats would be in place by the 2015 general election. John Curtice, professor of politics at Strathclyde University, calculates that the Tories will need to be 11.2 percentage points ahead of Labour in the share of the vote to win a majority on the current boundaries. The required lead would have been only seven points if the new constituency map had taken effect in 2015.

Cameron loyalists dismiss the plotting as mid-term whining by a handful of malcontents, overblown by the media. But there is no smoke without fire and my smoke detector senses a whiff of complacency in Number 10. Big beasts lurk in the Tory jungle, including David Davis, the former shadow Home Secretary, and Liam Fox, the former Defence Secretary, although Mr Fox may be brought back into the Cabinet tent.

The search is on for a new figurehead to “unite the right” against the Prime Minister. Adam Afriyie, the millionaire MP for Windsor who attracted headlines last weekend, probably has 20 backers now. Tory MPs are being sounded out about a possible vote of no confidence in Mr Cameron before the next election, unless he improves his party’s prospects.

That would require 46 names – 15 per cent of Tory MPs. Cameron critics claim they could easily muster 46 but want a show of strength of about 100 MPs for a rival candidate (a third of the parliamentary party) to give them a better chance in the Yes/No confidence vote.

If Mr Cameron lost, he could not stand in the ensuing leadership election. So there would never be a contest between him and someone like Mr Afriyie. Nor would an outsider like the Windsor MP be likely to win the leadership, as Cabinet heavyweights with much more experience than him would enter the race once Mr Cameron was out of the frame.

There could be a wobble after this May’s county council elections, when Tory losses are inevitable. But the point of maximum danger for Mr Cameron would be after the June 2014 elections to the European Parliament, when the Tories could easily come third behind the UK Independence Party and Labour.

Rebels are surprised that they have not been reprimanded. “The dam was breached this week,” one said. In other words, the plotting won’t stop now that has started. “There are more malcontents than Number 10 realise,” one Tory insider says. “There are enough ex-ministers, never-will-be ministers, MPs in marginal seats who are starting to panic and MPs angry with Cameron because he’s walked past them five times with his nose in the air and not spoken to them.”

Another scenario is that most of the 140 Tory MPs who joined the Commons in 2010 stick with Mr Cameron for the 2015 election. His critics say they would oust him then if he fails to win an overall majority. One advantage of delay is that Boris Johnson might be a leadership contender by then – if, as I expect, he finds a Commons seat on the eve of the election, despite his protestations to the contrary.

That such discussions are even taking place among Tory MPs suggests Mr Cameron has a near-impossible job, leading a party that is almost ungovernable. His personal ratings are better than his party’s, unlike Ed Miliband’s. Mr Cameron must try to reassure a band of MPs who do not believe he is “one of us”, but needs to make a different, compassionate Conservative pitch to the public in order to win an election. The gulf will be apparent on Tuesday when a majority of Tory MPs will probably vote against his plans to legalise gay marriage.

It’s a vicious circle. Mr Cameron lacks the authority that an outright win in 2010 would have given him. His unforgiving MPs do not trust him to win next time, and so give him little room for manoeuvre. Ironically, by destabilising him, they could jeopardise the very election victory they seek.