Motorway gantry sign
A gantry spanning the motorway with blue overhead signs indicating two lanes exiting and two continuing ahead, and the following text.
Left-hand two lanes destinations: M25 Gatwick [Airport symbol] (M23); Heathrow [Airport symbol] (M4) .
Right-hand two lanes destinations: Sevenoaks; Hastings A21 .
Junction number: 5.
Our three lanes widen out to four just in time for this confusing situation: junction 5, Chevening Interchange, does not prioritise the M25 as the through route, so the A21 lies ahead and if you're going to continue our journey around London you need to move left.