The cross-bench life peer Baroness Beeban Kidron has called for all websites used by those under 18 to include a delete button, allowing them to edit or remove any of their posts at any time. The idea forms one of five "iRights," part of a broader campaign "to make the digital world a more transparent and empowering place for children and young people."

These iRights range from important general ones, such as a "right to know who is holding or profiting from their information, what their information is being used for, and whether it is being copied, sold, or traded" to a more practical suggestion for a right to digital literacy. The most problematic is the "right to remove," which would make it easy for every child and young person to edit or delete all content they have created.

That sounds like a good idea in theory. After all, young people do frequently post material that they might regret afterwards. They—and their parents—would certainly welcome the option to erase some of those less-flattering moments from a digital record that could haunt them for the rest of their (adult) lives. But however noble the intention, it is not at all clear how it would work in practice.

For example, there is the cut-off date of the 18th birthday. Before that, young people are supposed to be granted unlimited powers to re-write their history. After that, tough luck. Leaving aside the arbitrary nature of the dramatic change that occurs at midnight on the day of their 18th birthday, how exactly will online sites know when to allow users to delete material?

In an interview with the Irish Examiner, Baroness Kidron was tackled on this point. "The question of how they know you are a child is a torturous question," she told the paper. "There are plenty of companies that work on anonymous verification and there are ways websites can know that a kid is a kid without knowing who they are." Essentially, then, the good Baroness believes in techno-magic: those clever geeks will come up with some unspecified system that can work out a young person's age to the nearest day—or month, or year, depending on your gullibility—without even knowing who they are.

That's merely one technical reason why the system will be impossible to implement. Another is because of legal issues. Last week, Google politely but firmly refused to extend the so-called "right to be forgotten" from Europe to the whole world. As it wrote on its blog, "We believe that no one country should have the authority to control what content someone in a second country can access." Other Internet companies are likely to agree with that viewpoint, which means that at best they might block access to a young person's post for visitors from the UK, or possibly in Europe, but it would still exist for users in other countries (and for those who connect via VPNs, of course).

There's also the issue of copies of posts, whether authorised or not. Even if an Internet company agreed to delete a post from its system globally, there are almost certainly copies floating around online. These copies, or archived versions, are highly likely to be indexed by Google and other search engines. The disappeared, embarrassing post would still be there and still be embarrassing. At the very least, there might be a copy or two on the Internet Archive's Wayback Machine.

The best solution to what is certainly a real issue goes back to one of the other iRights: digital literacy. The sooner young people learn that something posted online with little thought is almost impossible to remove, the better it will be. Not just in terms of thinking twice before uploading that dodgy selfie, but also in terms of accepting the fact that it is likely to be there forever if they do.

We don't need a new right for young people to be able to re-write their online history, we need for society as a whole to be more tolerant of the fact that everyone makes mistakes when they are young (and when they are old) and that now those mistakes are going to be around for a long time, thanks to the Internet. Trying to change that fact by demanding a universal delete button is likely to be as successful as demanding the right to acquire unicorns.