From tomorrow’s Spectator.

Downing Street aides nervously run through the symptoms: a flat economy, poor press, leadership mutterings. Then they say, ‘It’s just mid-term blues, isn’t it?’ A second later, they add nervously, ‘It’s nothing more serious than that, is it?’ The truth is, nobody can be certain. There’s no reliable way of distinguishing mid-term blues from something politically fatal.

Part of the problem is that few Tories have anything to compare their current mood with. After 13 years in opposition, only a handful of them have been in government before, let alone in the mid-term doldrums.

When I put this argument to one veteran of the Thatcher years, he delighted in pointing out that there was at least one person in No. 10 who knew what mid-term was like under Thatcher. Patrick Rock is Cameron’s policy fixer, having worked with him as a special adviser to Michael Howard in the Major years. But before that, he was a mid-term Tory by-election candidate under Thatcher. He lost spectacularly.

Rock might soon be feeling dejà vu. The man who beat him in that 1984 Portsmouth South by-election was Mike Hancock and there’s increasing speculation in Westminster that Hancock’s behaviour — as detailed by Julie Bindel in this magazine (‘Sex party’, 2 March) — may be about to prompt another by-election there.

The details of Rock’s defeat are a reminder of how volatile politics was in the 1980s. Portsmouth South had never been anything other than Tory. In 1983, they had won the seat with a majority of the votes cast. But a year later they lost it, albeit narrowly, to the SDP-Liberal Alliance.

The constituency was Tory enough to return to the party at the 1987 general election. But in 1997, it was lost to Hancock again and the Tories have yet to regain it. In a sign of how their grass roots have withered, senior Tories now dismiss their chances of taking it back because they have so few activists in the constituency. Instead, all the talk is of Ukip and whether they can go one better than they did in Eastleigh.

A Ukip by-election triumph would certainly darken the Tory mood. Even though Ukip won converts from all three parties in Eastleigh, it seems to be costing the Tories more than anyone else. As one minister says with a note of despair in his voice, ‘There’s always going to be a protest party in British politics and the problem for us now is that the protest party is uniquely well-suited to take support from us.’

This May’s local elections are only going to deepen the Tories’ mid-term blues. They have 1,477 seats to defend compared to just 255 for Labour. Even the optimists in No. 10 are braced for a loss of several hundred.

The Tories’ problem is that the last time these seats were contested was in 2009, at the last government’s nadir. It was after those elections that James Purnell resigned from the Cabinet, saying that Labour wouldn’t win under Gordon Brown. Back then the Tories were at 42 per cent in the opinion polls and Labour at 31 per cent. Now, the Tories are bobbing around the 30 per cent mark.

If the Tories lost more than a few hundred of these seats, it wouldn’t mean that defeat was inevitable in 2015. But it would increase the panic in the parliamentary party. MPs would return to their constituencies to be confronted by vanquished councillors who blamed the coalition in London for their fate. The danger for the Tories is that it becomes a vicious circle: if those MPs then lambasted the leadership, it would make the party look divided and weaken its position still further.

The Prime Minister polls ahead of his party and it is hard to see anyone on the Tory benches who would do better than him electorally. But this hasn’t stopped some Tory MPs from agitating for a leadership contest. ‘No change, no chance’ — that old rallying cry of the Tory disaffected — is on the lips of too many MPs for the Cameroons’ comfort.

One Cabinet minister who has investigated the matter believes that 25 letters of no confidence have been sent to the chairman of the 1922 Committee. The rebels need 46 to prompt a vote, so if this is accurate, they’re more than halfway.

What then will snap the Tories out of their mid-term blues? I suspect it’ll take a sense that the party can win, or at least hold its own, in 2015. MPs who believe they’ll keep their seats keep their heads more than those who think they won’t.

The arrival of Lynton Crosby, who ran the Tories’ campaign in 2005 and has twice helped Boris Johnson to victory in London, has certainly boosted morale. Many of the MPs who feel that the Cameron set don’t get their constituents’ concerns believe that Crosby does. They’ve taken to crediting him with every improvement they see. After Cameron addressed the 1922 Committee on Monday night, one Tory backbencher — and occasional Cameron critic — said to me: ‘Much better, Crosby’s clearly honing him.’

Crosby’s return has coincided with an increase in the energy levels at Conservative Campaign Headquarters under the new chairman, Grant Shapps. Shapps is now seeing Tory MPs in marginal seats on a regular basis, ensuring that the party does everything it can to help them in 2015. Basic politics, of course — of a kind that the Tory high command has neglected for too long.

But for Tory MPs to really start to believe, the economy will have to pick up. A few quarters of sustained growth would change the political weather. Given that Osborne leads Balls as the public’s preferred Chancellor even in the current climate, one imagines that a recovery would put the shadow chancellor under acute pressure.

There is a question, though, about whether the Tory party really wants to snap out of its funk. Among a surprisingly large number of backbenchers there’s a sense that a spell in opposition and a renewal of the party’s radicalism might be for the best. One new Tory MP told me he was already thinking about the leadership contest that would follow a defeat. He had a list of the 250 colleagues he expected to survive and was busy working out which of the various contenders fared best with this group.

The Tories’ fate is in their own hands. If No.10 becomes more political and if the party is prepared to be patient then it has a good chance in 2015. But those are very big ifs.

Listen to James Forsyth discussing a Portsmouth South by-election (at 10:28)

Tags: Coalition, Conservatives, David Cameron, Spectator