This is incorrect, and without being rude it's false info like this that perpetuates around internet forums because people post it because they heard it from someone else on the internet and then people get into trouble.
https://cleardebt.co.uk/debt-help/debt-help-guides/out-of-date-debt
Big difference - you can most certainly be pursued for a debt after 20 years if the limitation act doesn't apply to your situation. Now we know in Scania's case that he's not in Scotland, and that he hasn't had contact about this debt before so he should be safe under this the Limitation Act. However as someone mentioned earlier, what's to say if they got hold of a recording of his voice when he calls, or a copy of his signature so they can then falsify that they had had contact within successive 6 years periods. These debt companies are hardly squeeky clean and as someone mentioned the website for this one was only registered less than two months ago. Be very careful!