I was working at a Wastewater Treatment Plant in Rainham, Essex and the
sewage entering the plant (which would normally be about 10C) was freezing
on the screen bars and forming an ice wall blocking the flow. An engineer
developed some in-situ heaters to prevent the whole system backing up.Also
the whole N/NE facing area had to be insulated with tarpaulins to prevent
the wind chill.This has never happened before or since as far as I know.

Dave
I recorded a 12-hr max of -9.2°C (08Z to 20Z) on 12 Jan 87
here at Warlingham, Surrey, 556ft (169m). The 24-hr max was -8.9°C.
It's a COL grade B station. It was sunny, with a snow cover of about 3
inches and a light ENE'ly. In the early evening snow started to fall
out of cloud so thin you could easily see the moon and it continued on
and off for another 48 hrs or so until a level depth of 39 cm (16") lay
in the back garden. Melted and measured it all came to 27.8 mm.
There were 10 consecutive maxima below 0°C and 3 below -5°C. The max
on the 12th seems to have been about the lowest anywhere but it was
probably about a degree colder a few miles to the south at the top of
the Downs at 877 ft (267 m).
The upper air sounding showed a DALR from the surface to about
700 mb and the 1000-500 mb thickness was 498 dam, a record or nearly so
for the region.
When I started recording in 1983 I thought the lowest max I
would ever record would be about -6°C, possibly -7°C, in a nasty
Sc-laden 15-kn ENE'ly. I could scarcely believe my eyes, out to the
screen every half-hour or so. The sun was out, there was a gentle
breeze, but it just wouldn't warm up!
Tudor Hughes, Warlingham, Surrey. TQ 3516 5955.