In Britain the most important meal on December 25th is Christmas dinner. Nearly all food is traditional although it changes through the time. In the nineteenth century, for example, goose was the traditional meat at Christmas. Now it is the turkey.
So a 20th Century British Christmas dinner consists of roast turkey with carrots, potatoes, peas, Brussel sprouts and gravy. There are sausages and bacon too. Then, after the turkey, there’s Christmas pudding.
Crackers are usual at Christmas dinner. These came to Britain from China in the 19th century. In order to open the cracker, two people pull a cracker from both ends. There is usually a small toy in the middle and a joke on a piece of paper too. Here you are an example of a joke:
Customer: Waiter, there is a frog in my soup.
Waiter: Yes, sir, the fly’s on holiday.
(Source: Customs and Traditions in Britain. Longman)