Thick fog could bring severe disruption to commuters for a second day this week across parts of England and eastern Wales.

A Met Office warning is in place for the fourth consecutive day, this time covering the Midlands, East Anglia, the northern home counties, Yorkshire and the Humber and parts of Cheshire.

North-eastern counties of Wales such as Powys, Denbighshire, Conwy, Flintshire and Wrexham are also included in the warning.

The warning began at 18:00 GMT on Monday and runs until 10:00 GMT on Tuesday.

Forty flights were cancelled at Heathrow Airport on Monday before fog cleared.

On Saturday night, thick fog blanketed parts of England and Wales, making an FA cup match between Altrincham and Notts County less of a spectator sport.

It also caused a 30-car pile-up on the M20 in Kent on Saturday leaving two people seriously injured, as well as a 19-car collision on the A303 in Hampshire.

On Tuesday, visibility could be reduced to less than 100m in places which could lead to further travel disruption.

Patchy fog could also develop outside the warning area where the skies clear.

Southern counties of England will see breezier conditions, which should help inhibit fog formation. However, sheltered areas could once again see some dense patches.

The fog will slowly lift and clear through the morning and many places will brighten up. However, in places where the fog is most dense, it could linger on for much of the day.

Fog is not unusual at this time of year, especially as the nights become longer and the sunshine weaker.

High pressure can often last for days meaning the air mass does not change and becomes stagnant.

However, this week the forecast is looking changeable.

An area of low pressure towards the south-west of the UK will push weather fronts northwards across England and Wales.

This will bring cloud, rain and brisk easterly winds later on Tuesday, making fog unlikely here on Wednesday morning.

It could still form to the north of the fronts across Northern Ireland and Scotland, however, and is most likely to develop across the Central Belt and the glens of the south.

Towards the end of the week, a cold front will sweep southward introducing a northerly wind and arctic air with a lower dewpoint.

This means widespread fog will become much less likely, although there will be morning frosts.

The Met Office advises drivers to check road conditions before setting off and use fog lights when visibility is seriously reduced. Visibility of 50m or less can cause severe travel disruption.

Allow extra time for journeys and adjust plans if necessary. Patchy fog can be particularly dangerous because visibility can change suddenly.

The RAC motoring organisation recommends allowing extra stopping distance between your vehicle and the one ahead.

AA president Edmund King said drivers need to be prepared to adapt their speed on the road.

"One of the biggest mistakes is simply following the rear lights of the car in front. It can give you a false sense of security and means you may be travelling too close to react safely if that vehicle suddenly stops," he said.

If you are using public transport or flying, check for updates from your operator and follow its advice.

Flights may be delayed because aircraft need greater spacing when landing in fog.