Smart Motorway gantry sign
A gantry structure spanning the motorway with electronic signals, blue signs showing a "tiger tail lane drop" where the left lane exits, the right hand two lanes continue ahead and the second lane from the left can go in either direction, and the following text.
Exit destinations: A404(M) High Wycombe; A308(M) Maidenhead.
Forward destinations: SOUTH WALES; Reading, Bracknell M4 .
Junction number: 8/9.
Junction 8/9 got its strange number because it replaced two junctions when the M4 was extended. Junction 9 was at White Waltham, now A404(M) junction 9A, while junction 8 connected to the A308 and was removed entirely.