The FTSE 100 market has been the single strongest of the developed markets in the month of December, up almost 80% of the time for a 2.2% gain over the last 39 years as depicted in the first chart below. This is the single strongest month in any year. The second chart is the weekly price graph of the index. Note the upturn in relative strength. The index will likely break above the overhead barrier at 7700. As with other markets most of the strength has occurred in the second half of the month. From December 15th through December 31st the index has risen 84% of the time. See the third graph and note the late month strength.
1-FTSE 100 Monthly Histogram
2-FTSE Weekly
3- FTSE 100 Daily Histogram for December
Source: https://www.forbes.com/sites/greatspeculations/2022/12/14/buy-the-ftse-100-for-the-holidays/