Coldest day in the south east  for four years: 

The 13th was the coldest day in SE England since late December 2000 when maxes last were recorded as low as zero to minus 1C in this region. (Norwich recorded 0C on the 28th of December 2000, Heathrow recorded 1C on the 29th of December 2000 and Brighton recorded 0.5C on the 29th of December 2000).

A shallow layer of very cold continental air was drawn up from France (most of which was sub zero all day with maxima just -2C at Reims and 0C at Paris) to affect Southern & Central England plus Kent and Essex. The flow was cut off during the afternoon however under a thick layer of stratocumulus, temperatures near to, or in the case of Biggin Hill, below freezing, struggled to recover at all however.

http://www.wetterzentrale.de/archive/2004/brack/bracka20041213.gif

Maxes across the SE on 13^th December