December carries the two most widely observed bank holidays in the United Kingdom: Christmas Day on the 25th and Boxing Day on the 26th, both marked in all four nations. Where either falls on a weekend the day off moves to the following working day, so a Christmas at the weekend produces holidays running into the following week.
Leave in December 2028 is the most contested of the year. The two bank holidays sit close enough together that three or four days of annual leave covers the whole stretch from Christmas Eve to the New Year, and in shift-based industries the same days are the hardest to get cover for.
The move from December into January takes the country over the turn of the year without a pause in the school holidays, which run on into the first week. December 2028 hands over the shortest days of the year to the month where the light starts coming back.