The Met Office has issued a yellow warning for freezing fog in much of the Anglia region.
Freezing fog is reported at Stansted Airport as temperatures there dipped below -6C.
Fog, dense and freezing in places, is likely to become widespread on Tuesday evening and overnight into Wednesday morning across much of central and eastern England and into the London area as well as parts of northwest England. The fog will only slowly thin on Wednesday morning, but a few fog patches may persist all day in parts of the east.
Visibility will reduce to below 100 m in places and therefore the public should be aware of the risk of disruption to travel.