The fact that no one knows why Boxing day is called what it is shows how old it is and that it has lost its meaning. Traditionally you spend Christmas with family and Boxing day with friends.
But in the last four or five years America's tradition of Black Friday has crept in. You can tell that the major British stores have hired American advertising companies; going all out with early morning sales and loss leader items.
So there in lies the paradox. Normally stores are closed on Boxing day, but now some aren't. They have huge advertisements that the stores that do stay closed feel like they are fading into oblivion, so they advertise Boxing Day sales too. But, they stay closed. Their advertisements say the sales are the 26th and 27th and on the very next line it says the store will be closed on Christmas and Boxing day. So when you go to the shopping center all of the stores have up banners and decorations for the sale, some just don't have any lights on.