The Thicket Roundabout

The Thicket Roundabout is at the western end of the Maidenhead Bypass. It is junction 9B of the A404(M), and was previously junction 9 of the M4.

The motorway here has changed number four times. It was planned to be the A4(M) Maidenhead Bypass, but at the very last moment its number was changed to M4. The junction was a standard roundabout as commonly found at the end of motorways in the 1960s.

In 1971 the M4 was extended, and this section of motorway was renumbered A423(M). The junction was rebuilt in around 1991 to gain its present underpass, and as one of a number of road number changes the motorway became A404(M).

Routes

Route	To	Notes
A404(M)	Reading, Slough, Windsor (M4)
A404	Wycombe, Marlow, Oxford (M40), Henley (A4130)
A4	Reading, Littlewick Green, Business Campus, Knowl Hill, Twyford (A3032)
A4	Maidenhead
M4	London, Slough, Windsor	renumbered when the M4 route heading south of Reading was chosen
A4(M)	London, Slough, Windsor	renumbered when the Slough bypass opened
A423(M)	Reading, Slough, Windsor (M4)	renumbered when the A404 corridor was upgraded and the underpass put in
A415	Henley	renumbered as A423 in 1935. Actually met the A4 a little to the east.
A423	Oxford, Henley, High Wycombe, Marlow (A404)	renumbered when the A404 corridor was upgraded and the underpass put in

Links

{{Legislation|

• A423(M) Motorway (Maidenhead Thicket Section) and Connecting Roads Scheme 1987

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