Anti-Brexit campaigners demonstrate outside the Houses of Parliament on April 16, 2018 in London | Jack Taylor/Getty Images Opinion Europe to Britain: Eat your cake and go Stop acting like a spoiled child and accept that you can’t have Brexit both ways.

BERLIN — You Brits are known for many cool things, and high among them are the Rolling Stones. It’s likely that more of us in Europe can recite the band’s lyrics than can remember the sonnets of Shakespeare. Who hasn’t heard Mick Jagger’s abrasive voice reminding them that “You can’t always get what you want”?

Here’s an update, a soundtrack for the age of Brexit: You definitely can’t get one thing and also its opposite. Yes, we indulged you while you were part of the European Union. We gave you your rebate. We allowed you to sit on the sidelines of Schengen and the euro. But those days are over, now that you’ve decided to go.

It’s time for you to stop acting like a spoiled child and accept that you can’t have everything both ways — departure from the EU but membership in programs like Galileo and Erasmus; an Irish border that’s both closed but somehow open; access to the single market without its most important conditions; the freedom of movement and no oversight by the European Court of Justice; your pick of the European cherry tree, without bothering to water the soil or tend to its branches.

So please, eat your Brexit cake and go. But keep your sticky fingers off our slice of the pie. Or better yet, stiffen your famous upper lip and admit you made a huge mistake. Own up to the fact that British public opinion was instrumentalized; that the Murdoch press doesn’t represent the interest of the country’s citizens; that there’s no £350 million a week to spend on the National Health Service; that the Brexit referendum is more reflective of the misuse of private data by Cambridge Analytica than the will of the people.

Deep in your heart, you know that would be the right thing to do. If not, why are so many Brits hunting for European passports — German, Spanish, Irish, Maltese, whatever they can get? Why are your youngsters leaving? Why is Brexit tearing families apart, making it impossible for parents and children, brothers and sisters to share a happy meal?

There’s still time to reconsider the supposedly “inevitable” Brexit, which nobody over there seems to have any idea how to make work anyway.

Why are global companies pulling up and leaving the U.K.? Why is the City of London getting so nervous? Why are your academics looking for jobs abroad? Why doesn’t anybody serious want to work for the Department for Exiting the EU, which has been desperately hiring inexperienced youngsters straight from school? Why are your political leaders so timid about this whole Brexit thing? Why do you no longer have any real leaders?

Chin up, Britain. You were the country that introduced the Magna Carta in 1215 and then, after the Glorious Revolution of 1688, gave the world modern parliamentarism. Your John Locke laid down the foundation for representative democracy, allowing governments that failed to promote the public good to be brought down and replaced. Wouldn’t it be time to excavate these books in the British Library and study them again?

There’s still time to reconsider the supposedly “inevitable” Brexit, which nobody over there seems to have any idea how to make work anyway. One thing is clear: It will cause a lot of unnecessary damage on continental Europe, even though we didn’t have a right to vote on it. Isn’t it time to realize that you too are citizens of Europe — as you agreed to be under the Maastricht treaty — and that when it comes to decisions with such far-reaching implications, we should all make them together?

So, if Brexit is starting to look like a mistake (and, well, that’s exactly what it looks like), it’s not too late to rethink your decision. And we promise: If you come back, we can reform the EU together into a democratic and social Europe, so that nobody needs to leave it anymore! Stop trying to have everything both ways. Fight it out among yourselves. Figure out what exactly it is you want. And then, well, you just might find, you get what you need.

Ulrike Guérot is founder and director of the think tank European Democracy Lab, and professor for European policy and the study of democracy at Danube University in Krems, Austria.