Originally Posted by
alanR
Indeed, it's only recently that the UK government discovered a loophole in travel from Brussels by Eurostar. (Well actually they've known it for years but haven't bothered to do anything about it)
There are other ticket swap loopholes that have existed at Heathrow and Gatwick for years, with full knowledge of the powers that be. Its only in the last 10 years that the actual will to plug the holes has developed.