Smart Motorway gantry sign
A gantry structure spanning the motorway with electronic signals, blue signs showing the left lane exiting and three others continuing ahead, and the following text.
Exit destinations: A10 ; London (N&C); Enfield; Hertford.
Forward destinations: (M1, M40, M4); Potters Bar (A111); Watford, Heathrow [Airport symbol] M25 .
Junction number: 25.
This exit comes just as we emerge from the tunnel, and serves a very busy junction since the A10 is one of the fastest routes in to this part of suburban North London and also out to Hertfordshire.
The motorway from here to J24, a short one-junction hop, opened in August 1981.