Ever since last year’s general election, when Jeremy Corbyn inspired the strongest Labour surge since 1945, the Conservatives have been unsure if this was a freak occurrence or the start of something bigger. As they have learnt to their cost, opinion polls aren’t as reliable as they once were: only election results matter. There will be plenty next month, with seats on more than 150 councils all over England up for grabs. The Tories are nervous in lots of areas. But what terrifies them is London.

The capital has served as the incubator of Corbynism, a brand of politics once laughed off as a niche Islington interest, yet now with an undeniable national appeal. All 32 London boroughs are up for election, and nothing is certain. Not so long ago, the Tory party knew that — no matter how bleak the national picture — there were parts of the capital that would always remain blue. Westminster, Kensington and Chelsea, Wandsworth — these boroughs were the jewels in the Conservative crown. Even at the height of Tony Blair’s popularity, the party held on to them. Campaigning in their smarter postcodes was considered almost déclassé.

But this year, the Tories are in the fight of a lifetime to keep hold of every one of the nine councils they control. For many ministers, the working assumption is that the city is about to be painted red. As one cabinet minister puts it: ‘There is only one word to describe the party in London: screwed.’

For an idea of how bad things look, consider the Tory peer and psephologist Robert Hayward’s recent projection that the Conservatives will lose about 100 council seats of their 612, which would be a worse result than in 1994, just a few years before Tony Blair’s first landslide. That the Prime Minister recently chose to sit down with her nemesis George Osborne, in his role as editor of the Evening Standard, is a tell-tale sign of the depth of her concern.

The extent of the panic among London Conservatives has been so great that they have been considering a drastic step. Over the past year, a series of meetings has been held at venues including Tory HQ. On the agenda was a radical idea: that London’s Tories should formally break away from the national party and become a separate entity with their own brand and leader, like the Scottish Tories under Ruth Davidson. It would create clear water between them and a national party that, in the words of one insider, is becoming ‘very provincial’ under Theresa May.

Borough leaders, Greater London Authority members, association chairmen, London’s remaining Tory MPs — the vast majority were in favour of the idea. But word came down from the very top: nice try, but it’s not going to happen. Someone familiar with the meetings reveals: ‘We are a very centralised party now — and we were told to shut up, basically.’ In another moment of desperation, the Conservative party asked Ms Davidson if her team — after their outstanding performance at the general election — would consider heading south to mastermind the London campaign. The answer was a polite but firm ‘no’. The Scottish Tories had performed an astonishing recovery — but it was not (just) due to a well-run campaign. The renaissance came after painstaking work to identify why national Conservatism wasn’t working in Scotland. It was a long process, and the London Tories have yet to make the first step.

In recent weeks, Tory MPs have been campaigning in London — and the experience has not been invigorating. ‘Our council leader in Westminster, Nickie Aiken, thinks she is going to lose. Our leader in Wandsworth thinks he is going to lose,’ says one. The two biggest problems on the doorstep are Theresa May, who seems to embody a Shires Toryism, and Brexit, which three-in-five Londoners voted against.

At times, it seems the London party has been too complacent, as if it assumed wealth and Toryism went together. ‘In Chelsea,’ admits one MP, ‘it has come as a big shock to them to actually have to get out on the doorsteps and talk to people in a way they have never had to do before.’ At most, CCHQ are said to be ‘not confident but not panicking’ about Kensington and Chelsea, which the Tories have controlled since its creation in the 1960s. But as one cabinet member says: ‘After Grenfell, you never know.’

With such gloomy predictions circulating — and polling showing that only three in ten Londoners associate them with low council taxes — Tories are getting their excuses in early.

Sadiq Khan is the biggest one, even if his name won’t be on the ballot paper next month. Since he was elected London Mayor nearly two years ago, the Tories have viewed him with a mixture of frustration and reverence. Some speak of him as a shape-shifting modern political genius: a Brownite turned Blairite turned Corbynite — but somehow the capital’s gay-friendly first Muslim mayor gets away with it. Khan is a ‘Teflon’ politician, says a London MP, echoing an old Labour complaint about Boris Johnson. A cabinet minister adds: ‘He has achieved almost nothing, but he is very good at politics. He’s seen as proof that if you vote Labour, the sky doesn’t fall in.’ A seasoned campaigner, alluding to private CCHQ polling, says they’re not even allowed to mention Khan to voters.

The Mayor also allows centrist Labour supporters to back their party guilt-free — without feeling that they are lending Jeremy Corbyn a helping hand. Unlike London’s Tories, Khan has set himself apart from the national party. The fear among many of them is a double-whammy of those centrist voters and young, highly motivated Corbynistas. Turnout, which could be as low as a third, is everything. In part, the Tories are relying on white van man turning out in outer London. It’s them vs Momentum.

Brexit is another of the big worries — and it is here that the national implications are most obvious. The fallout has already been seen in Putney, for instance, where Justine Greening hung on at the general election with only a 1,500 majority. Labour also won the crucial swing seat of Battersea for the first time since 2005.

Here, Khan — and others — are making the most of voters’ concerns. The Mayor did this by deftly commissioning a Brexit economic analysis, which said that, thanks to our departure from the EU, London’s economy would be smaller than it otherwise would have been by 2030. An examination of the small print showed this fall did not take into account immigration controls, so GDP per capita would actually be higher as a result. It’s a reflection of the state of the Tories that they have never pointed out that the Mayor’s much-hyped report claimed Brexit would make Londoners richer.

With the twin liabilities of Brexit and Mrs May, London’s Tories are doing everything they can to pitch their campaign at a local level. ‘This election is bins not Brexit,’ says one. They’re more likely to mention dog mess on the pavements than May’s latest trip to Brussels. The closest they might get to mentioning a national issue is Momentum taking over Haringey council, or rife anti-Semitism, and why that’s emerging under a hard-left Labour leader.

But even the local angle has its flaws. The decay of basic Tory infrastructure, for example, means the party is running out of foot soldiers. Things are so bad that, for the first time ever, CCHQ has paid for a full-time employee in every London borough to chivvy local activists. The aim is to hold the nine Tory boroughs — and hope that, during canvassing, ‘we don’t wake up anybody who doesn’t like the party nationally’.

The ageing Tory activists fit a broader trend. London’s demographics are turning against the party in a way that suggests national trouble ahead. ‘Our core vote is 65 and white,’ says a councillor, adding pessimistically that — across Britain — ‘in 20 years’ time our entire vote will be either dead or 15 years from dead.’ The average age in London, the sixth youngest city in the UK, is 36.

If the Tories can’t cling on in the capital, what does the future hold? Already, some Conservative MPs have been canvassing in parts of Kent and Surrey — true Tory heartlands — only to hear on the doorstep: ‘I’ve just moved here from Hackney and I’d never vote for you!’ This may be a taster of what has been called ‘Londonisation’: mobile, educated, liberal youngsters from the capital who lean away from Conservative values and are starting to move elsewhere.

Certainly, if Labour can take control of urban areas, where house prices are higher thanks to gentrification (and what one councillor called ‘hipsterisation’), the Conservative party may see a knock-on effect years later in the suburbs and countryside. London would be easier for Tories to write off if it weren’t for the fact that its political trends can anticipate those of the rest of the country. The first sign of the Tory revival that led to David Cameron’s 2010 election win, for instance, was that the party did better than expected in London in 2005. After May’s leadership, the debate may be more about whether to forget the capital altogether and instead concentrate on Labour seats in the North and the Midlands.

Perhaps even more than age or housing, it’s race that ought to concern the Tories. Just 20 per cent of Londoners were non-white at the 1991 census. That has since doubled. David Cameron’s head of strategy once lamented that ‘the no. 1 driver of not voting Conservative is not being white’ — which was certainly true in 2010, when just 16 per cent of ethnic minority voters supported the Tories. That jumped to 23 per cent in 2015, helping Cameron win his majority, but sank back to 19 per cent at the last election. Given wider demographic trends, the longer-term problems for the Tories are obvious. Some MPs are said to think the party can win the general election in 2022 but will lose massively five years later because of how much Britain will have changed.

There are more optimistic voices. Mrs May’s assured response to the Salisbury poisoning might have helped in recent weeks. And some Tories think the gloom is either overdone or self-fulfilling. As one MP puts it: ‘If you go around predicting doom, saying the Tories are going to be wiped out in London, don’t be at all surprised when it comes true.’

His defiance might be wise. Politics doesn’t tend to follow demographic or economic trends rigidly, especially if politicians work to get ahead of those trends. London might be the first place to show left-leaning voters baulking at the more realistic prospect of Corbyn in power — the 1,500 protesters who rallied against anti-Semitism in Parliament Square last week clearly indicated the shine was coming off his leadership. Not to mention the 17,000 people who have quit his party in the past three months.

But politics is unpredictable. Right now, the only thing that can be said with confidence is many Tories are expecting to lose in London — and expecting that defeat to embody their wider problems. Will they be right? We’ll start to find out next month.

At times, it seems as if the London party has assumed that wealth and Toryism go together

Spectator.co.uk/podcast Will Heaven, Andrew Gilligan and Pippa Crerar on Corbynism and the capital.