Motorists in parts of Bedfordshire, Buckinghamshire, Cambridgeshire, Hertfordshire and Northamptonshire have been warned of difficult driving conditions due to fog.
The Met Office issued a yellow weather warning, advising that overnight fog is expected to persist until around 09:45 GMT. Visibility could drop to less than 100m (328ft) in some areas, particularly in rural locations. Drivers are urged to use fog lights while on the road.
The fog may also affect train services and flights, although no delays had been reported at London Luton Airport as of 07:00 GMT.
