The last time the Thames river froze hard enough for a frost fair was 1814 the last little ice age. We are likely heading into another one now.
Entirely possible another Ice Age. There are reports the Gulf Stream that warms Europe is slowing down. Greenland ice is melting, the north Atlantic surface water becomes less salty, since freezing makes it more salty and heavier, this means it is not sinking down to the bottom of the ocean which is what drives the Gulf Stream. Saltier water goes to the bottom, spreads south and in the south the warm Gulf Stream heads north. If it stops completely, move south and grab your thermal underwear.
In the short run, in addition to the 11 year cycle, there are 22, 44, and 88 year cycles. See also my Comment #47.