A-road gantry sign
A gantry structure spanning the road with overhead green signs showing an exit and the following text.
Forward destinations: (M20, M23) Gatwick [Airport symbol] A282 (M25).
Left turn destinations: Swanscombe, Erith, Bluewater A206.
Junction number: 1A.
You can also get to Bluewater if you stay on and go via the A2, and doing so will save you wearing out your steering on nine roundabouts.