Article from the BBC: https://www.bbc.com/news/uk-england-50807966
Lists the expected delays on the roads, and closures on the trains over Christmas (over and above nothing running on Christmas Day). This is the usual story of Christmas cheer, happens every year.
And every year (including this year) there are posts from oversees visitors "How do I get from A to B on 24/25/26 December. I can't seem to find any trains?".
There is no answer, you can't. No UK resident would have planned to travel on those days without planning it weeks or months ahead, and allowing plenty of extra time.