As of 2020, combining the length of the M11 from Wanstead in London before becoming the A14, then continuing as the M6, having it become the A74(M) and M74 until the junction with the M8 in Glasgow, the entire road network combined forms the longest continuous motorway in the United Kingdom and one of the busiest. It incorporated the Preston By-pass, the first length of motorway opened in the UK and forms part of a motorway "Backbone of Britain", running north−south between London and Glasgow via the industrial North of England. It is also part of the east−west route between the Midlands and the east-coast ports. The section from the M1 to the M6 Toll split near Birmingham forms part of the unsigned E-road E 24 and the section from the M6 Toll and the M42 forms part of E 05.