From "the missing Crypto Queen" (a BBC story on the OneCoin scam):
He takes the first one on the list and looks it up on the Companies House website. Everything is meant to be transparent - the website contains the details of every company in the UK. It's thought to be a key anti-corruption tool. "We are very proud of this in this country," he says. "The problem is that when you create this company, no-one checks any of the information provided." He clicks to see the company's filing history, but where you should see company accounts, there is nothing. "This is classic," he exclaims. "Look, nothing has happened. They have filed no financial information at all." Then he tries checking the company's owners. The UK began to insist recently that companies must enter the name of the person with "significant control" - the real owner.
"This is supposed to mean that you can no longer use a British company to hide behind," he says, as he scrolls down the page. "Oh, hey presto, they haven't filed a person with significant control. That's illegal… That is an anonymous shell company, as anonymous as anything that you can buy anywhere in the Seychelles or Nevis or the Marshall Islands or Vanuatu."
According to Wikipedia, Companies House is
the United Kingdom's registrar of companies and is an executive agency and trading fund of Her Majesty's Government. It falls under the remit of the Department for Business, Energy and Industrial Strategy and is also a member of the Public Data Group.
So basically, it's a UK government agency that among other things fulfills the role of business register.
Does Companies House do any checking whatsoever on their business registration data? How could someone file an empty form, i.e. no person of "significant control" whatsoever? Or is the story wrong and it is/was legal in the UK to still file such anonymous shell companies?