Magic Roundabout (Hemel Hempstead) viaduct. The BP building was found to be unstable due to defective reinforced concrete and the exit had to be closed. The building was demolished but the original route was not restored, although a newer side exit from the roundabout replaced the junction with Marlowes off a side road. Magic Roundabout (Hemel Hempstead) The "Magic Roundabout" in Hemel Hempstead, Hertfordshire, England, is the familiar name given to the Plough roundabout. The familiar name comes from the children's television programme, and is also used for a similar junction in Swindon and the M40 junction in Denham. The official name relates to
Magic Roundabout (Swindon) five mini-roundabouts and the outer loop. The complex junction offers multiple paths between feeder roads. The outer circle carries traffic in a clockwise direction, like a normal roundabout (in places where traffic drives on the left hand side of the road), and less proficient users may choose to use only the outer circle. The inner circle carries traffic in an anticlockwise direction, and more proficient users may choose to use the alternative paths. Virtually the same overall configuration has been in place for years. When the roundabout complex was first opened, the mini-roundabouts were not permanently marked out and could