Spending Christmas Day in the United Kingdom isn't so much different than in the U.S. It is, after all, mostly the British tradition of Christmas that we tend to follow.
The are some conspicuously differences though. For one thing on Christmas Day EVERYTHING closes down. No stores are open, restaurants don't serve food and public transportation does not exist. There are a few private taxis that can move you around but otherwise you walk or stay at home.
Interestingly, showing the social side of Christmas, are the pub hours. Though the pubs are closed for most of the day they do open from noon-3 p.m. This is so neighbors can gather after church to meet and share a Christmas pint before the big meal.
I get the feeling the holiday is celebrated more privately than in the states. Certainly it is a lot less commercial. Stores are decorated, but not overly. Most light displays are at public gathering spaces and traditional places. Few homes put lights outside the home and in the insides I've visited are decorated modestly - but tastefully. Television is not overloaded with fabricated Christmas specials. I did see the film version of "A Christmas Carol" (Patrick Stewart version) but not "A Christmas Story" or "It's a Wonderful Life." (see last blog).
Most importantly the gift packages under the trees are restrained. There is little garish or extravagant about Christmas in London.
But it is celebrated with sincerity. I was actually chided after wishing someone a Happy Holiday and told "Here, it's not politically incorrect to all say Christmas." And when people do wish you a Happy Christmas it is spoken with a quiet sincerity. Here Christmas is religious holiday celebrated in true ecumenical fashion.
However, the Brits do have their traditions. There is Christmas pudding which everyone admits tastes terrible but is served because "it's tradition." Then there is mulled wine. It's wine heated with fruit and spices - and while each variety is good there is a lot of creativity with individual recipes. The most fun is the Christmas Crackers - which is similar to pulling a drumstick. The winner who ends with the bulk of the cylinder gets the rewards found inside - a little prize like a notebook, costume jewelry or a nail clipper. The most important reward is a paper hat or crown that everyone willing wears the rest of the evening.
The traditions might vary but the spirit is the same - good food, good friends and good will.