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: A329(M) [Hollow circle diversion symbol] ; Reading (E); Bracknell, Wokingham.
Forward destinations: London, Maidenhead M4.
Junction number: 10.
The little A329(M) runs from the edge of Reading to the edge of Bracknell. It was meant to be the start of something much longer and more impressive, which explains its huge free-flowing junction with the M4.