The Duke and Duchess of Sussex’s new baby will be eighth in line to the throne, which should be a source of great joy to the Commonwealth – not least because it pushes the Duke of York one further down the line of succession.

To achieve celebrity status and win a place in the nation’s affections you have to give up your political ambitions

That the announcement has been met with snorts of derision and sarcastic tabloid headlines illustrates the uneasy dynamics of power, fame and public adulation in the twenty-first century. Since leaving the Royal Family the Duke and Duchess have launched a podcast, a production company, and are primed to give Oprah Winfrey a tell-all interview on 7 March (all at the same time as suing a British newspaper for intruding on their privacy). They traded a constitutional role and a fixed place in national life for something much more mutable – celebrity – and lost public affection in the process.

When it comes to power and celebrity, it’s always a trade-off. But it’s often claimed that social media and the 24-hour news cycle has birthed a monstrous hybrid of the two, and that Boris Johnson and Donald Trump represent a new kind of celebrity politician, leveraging fame to gain political office.

There is a compelling narrative that the former president’s main qualification for the job was his starring role on The Apprentice, that his style of governing via Twitter owed something to the celebrity playbook, and that his term in office was a kind of apotheosis of his stardom – but this doesn’t allow the American people much agency.

And in any case, Johnson’s career has followed almost the opposite trajectory. It’s not quite correct that Boris was a media personality who threw his hat into the ring for London Mayor and snatched an unlikely victory, as the BBC seems to suggest. In a recent BBC documentary, Celebrity: A 21st Century Story, Ed Balls contended that: “Boris’s celebrity from Have I Got News For You helped him. In an era when politics was becoming less popular, Boris put himself on the outside and that celebrity and outsiderness definitely worked to his advantage.”

That the turnout in the 2008 mayoral election was 10 per cent higher than in 2004 does suggest that Londoners were particularly engaged with this contest. But Johnson had already been a columnist, an MP for seven years, and a shadow minister, so he was a funny sort of outsider. And it’s not as though his opponent was some cringing wallflower – it was Ken Livingstone.

A strong media persona is pretty much a prerequisite for the role of mayor – ask Sadiq Khan, who’s increased City Hall spending on PR by 33 per cent since taking over. But there’s a difference between being well-known and being a “celebrity”.

It’s difficult to maintain a humorous image when over 100,000 people have died in a pandemic

Whether Johnson’s amusing TV appearances helped him get elected in 2008, it’s a bit of a stretch to say they had a direct influence on him becoming prime minister 11 years later. His most popular appearance on Have I Got News for You was viewed by 7.15 million people – more than 17 million voted to leave the EU. Rather than reaching new heights of public adulation, what Johnson is arguably most associated with now – Brexit – is essentially a trade policy. And it’s difficult to maintain a bumblingly humorous image when over 100,000 people have died in a pandemic and you’ve placed the country under house arrest.

Ed “glitter” Balls should know better than anyone that to truly achieve celebrity status and win a place in the nation’s affections you have to give up your political ambitions. He told the BBC that after his appearance on Strictly Come Dancing people would say to him: “We always knew you were a politician, but now we know you’re a human being.” It’s heart-warming stuff, but it’s difficult to imagine he’d have appeared on the show if he’d still had a shot at high office. You won’t see George Osborne or Sajid Javid slipping into the sequinned tuxedo any time soon – or even Chris Leslie, but that might be because he hasn’t been asked.

I’m not sure we really want our politicians to be dancing to Gangnam Style on TV on a Saturday and standing at the despatch box the following Monday. Many of the celebrities interviewed for the documentary speak movingly about the Faustian pact they struck with fame. Made in Chelsea and I’m a Celebrity star Georgia Toffolo said: “If politics was to learn anything from reality TV, it’s that the more authentic you are the more people want to engage with you. Reality TV stars bare their soul, sometimes for the entertainment of others, and for that they have hundreds of thousands, maybe even, in lots of cases, millions of people following them.”

When politics, celebrity and public affection combine the mix curdles – you can’t have all three

Some Tory MPs who won Red Wall seats in 2019 would certainly agree that “authenticity” is a useful currency, and that social media helped them connect with voters who’d felt ignored by the Westminster machine. But it’s not the only thing we look for in our leaders. It was often claimed that Jeremy Corbyn was “authentic” because he refused to dress smartly or change his mind about anything. Surely his time as leader proves that followers don’t necessarily mean votes. And the likes of Lembit Opik, Robert Kilroy Silk and the Hamiltons are a cautionary tale about the dangers of over-exposure.

A politician can be a poor media performer but a competent administrator; it doesn’t mean they’re not good at their job.

The promise of celebrity is that you can have power, fame and that people will love you. But Ed Balls only became a national treasure after giving up politics; Boris Johnson moved away from celebrity to become a more serious politician; Georgia Toffolo is famous and adored by her followers but gave up her personal autonomy to achieve that; and Meghan and Harry have given up power of sorts and lost the love of the British public.

When politics, celebrity and public affection combine the mix curdles – you can’t have all three.