Change Route: M4 Heathrow Spur

Junction 4 is unique (as far as I know), in that it has 2 motorway spurs leading from it, and both are parts of the M4 rather than having their own number. The north spur is very short and leads to the A408. The south spur is about a mile longer and heads down to Heathrow at Junction 4a. Leave here if you'd like to explore the spur, or maybe catch a flight.