http://britishfood.about.com/od/festivecooking/tp/thnksgvng.htm
Thanksgiving isn't a celebration in the UK - the nearest equivalent is Harvest Festival where we give our thanks for food and the years' harvest. With so many Americans living in the UK and the close alliance this country feels for its American cousins, Thanksgiving in the UK is certainly gaining momentum.
A surprising number of restaurants around the country serve a Thanksgiving dinner and there are a number of festivals taking place.
http://www.huffingtonpost.com/2014/11/26/britain-thanksgiving_n_6225622.html
LONDON (AP) — Plump turkeys in butcher shop windows. Harvest displays of pumpkin and corn. Sandwich boards describing groaning feasts.
Thanksgiving isn't a holiday in Britain, but you might be forgiven for being fooled. It's not hard to find someone to talk turkey, never mind sell you one. That's because there are so many Americans in Britain these days that dozens of businesses have started selling the goods they need to celebrate.
Greg Klaes, a Detroit native who used to teach science on U.S. military base schools, started growing pumpkins 30 years ago so his students could carve Halloween jack-o-lanterns. This year, his Oxfordshire farm is selling 600 kilograms (1,322 pounds) a week, filling harvest decorations and pumpkin pies.
And since there's no other holiday that's quite like Thanksgiving, businesses big and small are finding ways to get in on the celebrations. Dozens of restaurants are putting on spreads. Texas-based Whole Foods has turned its store on Kensington High Street into a one-stop holiday shopping center beginning with a sidewalk chalkboard that welcomes customers with the message "We are here to make your Thanksgiving epic."
Even the mainstream British grocery chain Waitrose is getting involved, although in a smaller way. A few blocks down the High Street in a store that's already decked out with red-and-green Christmas decorations, Waitrose has a small "Happy Thanksgiving" display, complete with a picture of a pumpkin wearing a buckled Pilgrim hat.
Britain doesn't really have a holiday like Thanksgiving. There are harvest celebrations, but no single event compares to the mammoth festival of food and football that dominates American thought. Britons know about it, though, and in a world of multinational companies, they will expect their colleagues to be away on Thursday.
"I'm personally quite envious of your Thanksgiving." Joy said. "It's about family and friends. It's all about being proud to be an American. It's all about not giving presents, but it's about your presence. It's about being there and being part of a family."
http://www.telegraph.co.uk/news/worldnews/northamerica/usa/10480219/A-British-guide-to-Thanksgiving.html
What is Thanksgiving?
Thanksgiving is celebrated in the United States following the traditions of the first Pilgrims and Puritans at Plymouth (Massachusetts) who, legend has it, were thankful for a good harvest in 1621.
Historically, Thanksgiving has its roots in harvest festivals and days of religious worship, and Canadians celebrate a separate Thanksgiving also drawing upon these origins a little earlier in the year
Can I celebrate it in the UK?
Yes, it’s becoming increasingly fashionable for restaurants and pop-ups to host Thanksgiving meals. Try Joe Allen in Covent Garden, London or Gordon Ramsey's The Narrow in Islington.
Do we have our own equivalent?
Yes, it's called Harvest Day, although it's a lot less of a big deal. While we usually take a few cans of food down to our local church, Thanksgiving in North America is a much more plentiful and extravagent affair.
http://en.m.wikipedia.org/wiki/Harvest_festival