The turkey sits in golden splendor on the carving board. The cranberry sauce glows in its cut glass bowl. There's a large dish of Brussels sprouts, shiny with butter; stuffing flecked with sage; and heaps of crispy roast potatoes. But this is not a Thanksgiving feast. There is no green bean casserole, no mac 'n cheese and not a yam in sight. We've crossed the Atlantic, and this is the traditional Christmas dinner that Brits will sit down to on Dec. 25.