In Harry Potter 7.1 near the beginning, where is the freeway chase scene filmed. The high level bridge/tunnel and ramping look way cool.
Try the forum search: https://www.aaroads.com/forum/index.php?topic=368.msg83576#msg83576
To expand more on my original post (especially as the bridge was mentioned here, but not in my OP), it's the A282 Dartford Crossing - comprised of the Dartford Tunnel (http://www.sabre-roads.org.uk/wiki/index.php?title=Dartford_Tunnel) and Queen Elizabeth II Bridge (http://www.sabre-roads.org.uk/wiki/index.php?title=Queen_Elizabeth_II_Bridge). There's a toll which is there as a congestion charge, but the toll booths are the main cause of congestion in the area. They've recently changed it to be more that one coin, which doesn't help. There is a tag which gives you a discount (and a local discount on top of that).
And oddly the bridge must have 'been closed' when Harry and Hagrid go through the tunnel as there's buses to Dartford, and other opposing traffic as they head through from south to north, whereas southbound traffic normally takes the bridge (though can take the tunnel as it used to, but the congestion is a nightmare more than it is now).
I like the way that the High Speed railway line to London/Paris goes over the tunnel access, and under the bridge, on the northern side - it's quite cool.
As it's the opposite side of London to me, I rarely go on it as almost everywhere is easier to get to from my house if you don't cross it.
Oh, and it's not part of the M25 for several reasons - slightly different access restrictions to a motorway, original bore opened as A282 and a right of way was created and they are difficult to 'close' legally (motorways are not rights-of-way) and perhaps most importantly of all it's not worth the effort of changing it as there's no benefits other than a blue line on maps.