I think it might be safe to say that we're in the year-end stretch now. There isn't much to explain the drop in the pound today, with most other major currencies not doing a whole lot - the kiwi being the outlier as noted earlier here. Equities are faring better on the day but the pound is finding itself offered with GBP/USD falling by 0.7% to 1.2100.
The pair is now running towards another test of its 200-day moving average (blue line) at 1.2083 and that remains a key line in the sand in terms of limiting any further downside momentum.
For buyers, they have to keep price above that level to stay in the game. Otherwise, a firm break below that will see sellers start to flex their muscles and target a push towards 1.2000 first in the next leg.