The great Christmas getaway begins today, as people start to plan journeys home for Christmas.

The Independent's Simon Calder predicts that Friday 20 December is likely to be the busiest day of the winter season at London Heathrow airport.

If you're flying out of Heathrow today, leave plenty of time for your journey.

Passengers for Gatwick airport this morning should leave extra time for their journey,

The M23, which serves Gatwick airport, is closed between junctions 10 and 11 due to flooding.

Train operator Southern has warned that those wishing to travel between Gatwick and Brighton should reconsider their plans due to the flooding.

Twenty airports across the UK are this morning launching the One Too Many campaign to remind passengers about the dangers of drinking and disruptive behaviour over the festive period.

Warnings about disruptive behaviour will be displayed across digital screens, in retail, food and drink outlets in the airports, as well as through a targeted social media campaign, to encourage passengers not to drink too much.

More than 40 million passengers are expected to travel to and from UK airports in December and January, according to the UK aviation industry. The busiest day for air travel is expected to be Saturday 21 December.

Here's more information from Simon Calder on the Gatwick flooding this morning:

Images from Highways England show a lot of standing water on the M23 still, with the motorway still closed between junctions 10 and 11.

Train operator Thameslink is telling customers not to travel between Gatwick and Brighton due to flooding.

Trains between London and Gatwick are still running as normal.

BBC Sussex is reporting 2h 30m queues northbound on the M23 close to Crawley, while there are delays of an hour heading south.

All main roads in the Crawley area have very heavy traffic as motorists try to avoid the motorway and reach Gatwick, says Simon Calder.

While Brighton struggles with no train service...

Disruption on the railway line between Brighton and Gatwick is expected until at least 2pm today.

Sussex Police are trying to free motorists stranded by the flooding on the M23 south of Crawley, saying: "If you're stuck in the stationary traffic between J11 and the floods: we are trying our best to get you turned around, but please be patient: with the road closure on, there's a lot of traffic to move into a very small space at Pease Pottage!

"If you *are* stuck, please stay in your vehicles. With emergency services vehicles trying to get through the queues, pedestrians are very, very hard to spot in the dark. Stay safe and dry in your cars!"