The main story on the travel problems caused by fog will continue to be updated, and you can follow it here.

Goodbye and good luck if you're trying to make your way through the foggy conditions. 

The fog is clearing and this live page will soon go. Before we do, however, here's a round-up of some of the main points of the day.

Heathrow airport says about 45 flights have been cancelled due to fog, while London City was closed to all flights for several hours. It is now seeing a few departures.

Other affected airports include Manchester, Leeds Bradford, Glasgow, Belfast, Southampton and Cardiff.

Fog in Europe is compounding the problems, with major hubs such as Amsterdam's Schiphol badly affected.

Image source, James Mordaunt

The BBC London team has put together a Facebook album, external of shots of the capital in fog, which have been sent in by readers. You can send your own in too if you like. 

A reminder that British Airways is encouraging, external those whose flights are cancelled not to go the airport on Monday.

The airline says it will book affected passengers onto alternative flights so they can continue their journeys.

You may recall that the Met Office had yellow warnings, external for fog in place across England and Wales - they have now been lifted. 

Image source, EPA

Simon Williams from the RAC says drivers must be very careful in foggy conditions.

"We must make sure we leave plenty of room behind the car and in front. Don't be tempted to follow their rear lights in the fog, that could be an accident waiting to happen. 

"Also, off the motorway network, if you come to a junction and you really can't see what's going on, turn off the radio, turn off the music, and open the windows and listen as well. And obviously, if it's that bad, and you're off the motorway network, stop somewhere safe."

Looks like the delays at Heathrow may continue into Tuesday.

Image source, AP

Just a quick aside - think our fog is bad? Nasa scientists say they have found acid fog caused by volcanic eruptions on Mars. A similar phenomenon is apparently seen on Earth in Hawaii, where it is known as "vog". 

Image source, AP

Either someone has stolen the top of the Eiffel Tower, or it's a really foggy day in Paris. 

Image source, Getty Images

It's not just roads and runways covered in fog - here's a shot of Manchester United's squad, training in mist on the eve of their Champions League match against CSKA Moscow tomorrow. 

United haven't scored for more than five hours, so the last thing they need is the weather making the goal even harder to find.   

So in this day and age, when navigating your way around pretty much anywhere on Earth is as simple as getting out your smartphone, why can't planes fly in fog? 

Our BBC News Magazine team has found out the answers to this, so you can impress your friends when they ask the same question. 

It's not just the UK snuggled under a blanket of fog - swathes of the stuff are also causing disruption across western Europe, with low visibility leading to significant flight delays.

There were delays today at airports in Paris, Amsterdam, Frankfurt, Berlin, and Brussels, where visibility reportedly dropped to just 100m.

There is one in this video. Can you see it?

The Independent has also put a foggy picture of Europe together. 

An update from London City Airport - it's started to allow a small number of departures, having been closed for several hours. 

The Guardian has a nice round-up of atmospheric scenes from across the UK and Europe today. 

Image source, EPA

Now we know what you're thinking - this isn't fog, it's glorious autumnal sunshine. But look in the background and you'll see a blanket of the misty stuff spread out over Starnberg Lake near Tutzing, Germany. Let's hope some of that sun comes the UK's way soon. 

Image source, Getty Images

It's probably not a good day to play fetch with your dog's favourite ball, judging by the gloomy scene in this Peckham park in London.