Route
Junction number
12
Markerpost
46 km
Name
Portsbridge Interchange
Type
Non-standard interchange
Terminus
Terminus at end of exit list
Other routes
M275, A3, A27
Authority
Restricted turns
Some turns restricted
Services
No services
M27 J12 Portsbridge Interchange
Layout and signage
|
Portsmouth Continental Ferry  M275 Link Cosham Hilsea A3 |
M275 A3 |
|
A27 A3 |
Lane configuration
- Lane 1 exits and does not return.
- Lane 2 continues ahead.
- Lane 3 continues ahead.
- Lane 1 continues ahead.
- Lane 2 continues ahead.
- Lane 3 is gained from the entry sliproad.
Other events
Start of motorway regulations
End of motorway regulations
What's new
The road that made no sense
It was the UK's only single-carriageway motorway, and twenty years ago it ceased to exist. This is the story of the strange fascination it held, and of my place in history.
The forever bottleneck, part 2
The second part of the story, where we learn why exactly the M4 gets narrower on the final approach to Europe’s biggest city.
The forever bottleneck, part 1
The M4 into London was one of the UK's earliest and most ambitious motorway projects. It was bold, pioneering... and almost instantly regretted.
Have you seen...
Hogarth Flyover
It makes the traffic situation in one part of West London much more bearable but it should have been removed more than quarter of a century ago. It's amazing what you can do with a big Meccano kit.
About this page
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