On Thursday, I was celebrating my birthday with friends. Just before 10pm political curiosity got the better of us during pudding, and we crowded around an iPhone to confirm our bias and watch the exit poll return the Tories to a decent majority. When the waitress handed me the bill later, she said wryly – “No one else can believe it either”.

At her home in Maidenhead the woman who’d spent her entire life eschewing risk, the woman with the 20-point lead and the seemingly stratospheric approval ratings, couldn’t believe it either. Theresa May had rolled the dice and lost – a political self-immolation of epic proportions. Here’s five thoughts as to why…

1. When you are winning don’t rock the boat

May’s close-knit team were guilty of calling this election from the comfort of the echo chamber. Hubristically perhaps they believed their own hype. Warned against going to the country by Lynton Crosby they went anyway. It was an unnecessary risk without a clear purpose.

Portrayed as strengthening her mandate for Brexit, at a time when Labour had already voted for the triggering of Article 50, it began to look like it was all about annihilating everything in her path. Her massive poll leads soon proved to be both a millstone and a target.

2. If you are going to run a presidential campaign make sure you have a presidential candidate 

On the face of it this looked like a good idea. She looked like a leader. Where Labour at first refused to mention Corbyn, May was everywhere. Local candidates grinning alongside the Imperial leader, Theresa May emblazoned in huge letters, the word Conservative etched in invisible ink.

But if that singular message is found wanting, as it was over social care, then there really is nowhere else to go. May’s strengths as a PM, unwavering, indefatigable, proved her undoing as a candidate. Wooden, Maybotic, formulaic. Corbyn by contrast looked every inch what he was – a campaigner.

3. Have an aspirational message

Unlike Vote Leave’s “Take Back Control” – a message that was aspirational and something voters understood was in their hands – May’s “Strong and Stable” was about an individual and it was soon holed below the waterline. May wasn’t wrong to expose Corbyn’s record on terror, the weakness of his team, or his lack of leadership. But she needed to do so in tandem with a positive vision for the country, one that championed a hopeful future.

Corbyn gave voters that aspiration and hope. “For the Many not the Few” drew voters in. Promises on student fees, the NHS, and education kept them there. And he was lucky. The leaking of Labour’s manifesto gave him a week-long head start on policy – voters, many too young to remember the 70s, nationalisation and a British Rail train, quite liked Corbyn’s promises. Ukip voters simply liked his anti-establishment credentials.

4. Don’t alienate your base… And don’t then take them for granted

May had control of the timings and yet she went to the country with a manifesto for Mayite redistribution that could never have been properly road tested in the time available. It allowed the myth that Tory numbers in the manifesto weren’t costed and Corbyn’s were to be presented as fact. In truth, both sets of numbers were found wanting by the experts, but the idea took hold.

She was right to challenge the notion that social care was a massive problem and couldn’t be left unfunded. Somebody had to pay for it. Only it appeared that somebody voted Tory. Her core vote ended up hearing one simple manifesto message – vote for us and we will take away your Winter Fuel Allowance now and your house when you are dead. They hated it.

May uttered the words “nothing has changed” over social care to incredulous reporters and by extension millions of voters. It would prove very costly. By denying her U-turn on social care was just that, she compounded the manifesto mistakes. If she’d said, “strong and stable leadership is about listening, we have and we are changing the policy”, she’d have appeared honest, thoughtful and understanding. Instead she appeared petulant, even dogmatic.

5. At some stage the young were going to wake up, get out of bed and vote

And so it proved. The experts, this one included, simply didn’t believe the micro targeted modelling that emerged from pollsters like YouGov. There was no way 60%-plus of 18-25s would vote. They never had before. Wrong. Corbyn’s team successfully read the data – young people were there for the taking because they hated austerity and Brexit in equal measure.

Energised by the use of social media campaign tools, Labour built an army of Facebook advertising that swamped the under-40s in the days before the election. It seemed younger voters didn’t connect Labour’s woolly stance on Brexit to Corbyn. They were determined instead to flick a huge V-sign at their parents, grandparents, Brexiteers and the Tories over the referendum result. Many Tory remainers did the same.

What next?

Despite Labour’s assertion to the contrary May didn’t lose this election. She won 13 million votes and nearly 60 seats more than Corbyn. There is no appetite for change, or another election. She faces crucial tests in her alliances with the DUP, the passage of the now admittedly sparse Queen’s speech and the beginning of Brexit negotiations. She should be given the space to govern, and she needs to do so as a team captain.

When I was first asked to write this piece, I pulled out what might be deliverable from the Tory manifesto on marketing, advertising and the media – the detail on media regulation, data protection, digital, intellectual property, even employment law and immigration. I simply can’t tell you now. What stays, what goes, what’s promised, and most importantly what is deliverable. It’s an enormous test, but then again she is a much better PM than she is a campaigner.

A version of this post appeared on Campaign.