A4(M)
Where is it?
Well, it's not actually anywhere.
I get it. Where was it then?
Maidenhead, Berkshire
Maidenhead? Isn't there a load of little motorways there?
Yes, there is - the A308(M) and the A404(M) are around there.
Can you show me that on a map?
I certainly can, although an aerial photo show the whole thing in a much better way...
Ah, so this turned into the present day A404(M) then?
Not exactly, no.
The section of motorway between the present northern end of the A404(M), and M4 Junction 7 was originally built as the Maidenhead Bypass in 1961. This then became part of the M4 when the Slough Bypass section to the east was completed in 1963.
Between those two dates, the road went by its original name - A4(M).
What happened?
In 1971, the M4 was extended west, from a point roughly in the middle of the original Maidenhead Bypass. This left a small section of the original A4(M) surplus to requirements, and it was abandoned. The abandoned section is really obvious if you look in the middle of the aerial photo mentioned above.
What does the abandoned bit look like?
The abandoned section is split by the A308(M), and the northern section is not accessible by the public. The southern section, however, looks something like this...
Can I see the full version of the map above?
Yes, thanks to Simon Davies.
Can I comment on this motorway?
Of course! Contact me and I'll put them here!
Have any other visitors commented?
Richard Macer-Wright has found some early information about the Maidenhead Bypass:
Just wondered whether you had seen a clip from British Pathe - it rather suggests the Maidenhead bypass opened on the ground as the M4 and was only known by A4(M) in atlases
Andy Syms answers just why this bit was abandoned:
I lived in Reading in the 50's, 60's and 70's and my recollection was that the 'Maidenhead bypass' was always designated the M4.
The reason that a withered arm was left when the M4 extended westwards was due to a change of route. Originally the M4 was due to pass to the north of Reading but the 'posh' inhabitants of Sonning and Caversham raised merry hell about it and so the route was altered to pass to the south. It passes within a quarter of a mile where I used to live in Shinfield but fortunately I'd moved by then...