The proposed route of the M4 was then changed to go south of Reading, instead of north of it.

When the M4 was extended in 1971,[2] a new junction was provided to connect with what would become a spur.

A new junction (numbered 8/9 so as not to confuse motorists) was built.

A new spur, the A308(M), was built to maintain access to the A308 and connected with the A404(M) and the M4 at the same grade separated roundabout.

Note: motorway has no junction numbers Information above gathered from Advanced Direction Signs April 2011