Zac Goldsmith’s defeat was the worst piece of news for Conservatives in this week’s election results. Scotland was a triumph, Wales and England were ok but not great, but London was the big loss. City Hall has been Tory for eight years – and while its incumbent has sometimes caused Downing Street some headaches, it was far preferable to have a Blue Prince across the water rather than an outright enemy.

The post mortems began before the count did, with Andrew Boff denouncing the campaign on Newsnight as soon as the polls closed. Since then there have been various other contributions to the debate – Tim Montgomerie has argued Goldsmith fell victim to Crosbyism, Mohammed Amin has reported his dislike of the campaign’s messages, Andrew Roberts has ridden to the Conservative candidate’s defence. No doubt more is to come – and Goldsmith himself is reportedly considering a public statement on where things went wrong.

It’s undoubtedly worth assessing what did and didn’t work, as it is in any campaign – successful or unsuccessful. That’s how we learn, avoid mistakes and improve in future. I certainly think there would be some merit in considering whether Syed Kamall, who was defeated in the nomination process (and whom I voted for), might have run a rather different campaign and could perhaps have defeated Khan.

However, we shouldn’t get carried away – while London is obviously winnable for the Conservatives, it is easy to forget that Boris’s two mayoral victories were remarkable. It’s untrue to claim that London is inherently and inevitably a Labour city – 2008 and 2012 showed that – but it’s also a mistake to assume that a Tory incumbent in City Hall is always going to be the normal state of affairs.

In recent years, London has regularly delivered better results for Labour than elections in the rest of the country, and a huge proportion of Labour Party members now live in the capital, giving their ground operation great power.  The most acute assessment of what went wrong this time is arguably that of an unnamed Tory source in the Sunday Times: “The main problem was that we didn’t have Boris.”

We should also be careful not to overdo the gloom about Zac’s performance. As Tim Shipman noted in this morning’s Red Box email:

‘Yes, Goldsmith lost by a mile. But – as a senior Conservative contacted me to point out last night – he got enough votes to win every mayoral contest except 2008 and only 60,000 fewer than Boris in 2012. Most instructive is how he did compared with his party relative to Khan. Across London, Goldsmith (994,614) got 238,000 fewer votes than the Conservatives (1,233,386). Khan (1,310,143) got 234,000 fewer than Labour (1,545,080) as a whole.’

He lost, which is of course what matters most. And another campaign or another candidate might have won, so it was a missed opportunity, which we should regret. But the facts about Goldsmith’s total vote simply do not bear out some of the more extreme rhetoric about his performance. That doesn’t mean you have to approve of the messaging, or that it’s wrong to criticise it, but it does caution against viewing the whole campaign as an unmitigated and accursed disaster. (Personally, I suspect the messages about extremists probably brought out some sympathy voters for Khan, and almost certainly punctured Zac’s previously reasonable hope of winning a lot of second preferences from Greens and Lib Dems. The wider defeat seems to be far more about the energy of the campaign, or rather the lack of it, than about the issue which now hogs the headlines.)

We in the media are at risk of obsessing about the London result above all others. In part, that’s because the media is hugely London-centric (a fact seen in other fields such as arts coverage and economic news, too). City Hall is within a short journey of all of the national newspapers, and the vast majority of national journalists would have had a vote on the mayoralty. As a result, some are prone to forget that most of the country is outside London, and doesn’t give much of a hoot about what happens there.

The timing of the counts has added to that overblowing of the result. On Friday morning, the big news was the collapse of Scottish Labour, against a background of stagnation in England and Wales – so the Opposition understandably now wants to talk only about Sadiq Khan’s success. It’s a valid news story, but Labour’s interests shouldn’t be indulged at the expense of all other news. In 2020 the future of the country will be more greatly influenced by what happened in Scotland on Thursday than by the outcome of the 2016 London mayoral election.

There’s one really interesting aspect of the mayoral result which is yet to be discussed. A big victory for Labour in the capital stands in stark contrast to the fate of the Party elsewhere in the country. London already resembles a different nation to the rest of the UK in many ways – economically, socially, culturally, demographically and even in terms of the population’s reliance on public transport rather than cars. We can now add to that list a growing political gulf. Cumulatively, these differences have caused growing misunderstandings (and some resentment) between the rest of the UK and the city which is meant to sit at its heart. How the gap will be bridged – or if it can be bridged – is a challenge to which we are yet to hear an answer.