The Preston Bypass was the United Kingdom’s first motorway. It was designed and engineered by Lancashire County Council surveyor James Drake as part of a larger initiative to create a north-south motorway network that would later form part of the M6 motorway. The bypass was opened on 5 December 1958 by the then Prime Minister, Harold Macmillan. Nearly £3 million was spent in its construction. The original 8+1⁄4-mile (13.3 km) motorway ran around the east side of Preston between Bamber Bridge (now the M6, Junction 29) and Broughton (now the M55, Junction 1) and crosses over the River Ribble at Samlesbury at the M6 Junction 31.

Planning started in 1937, despite there being no legal powers that permitted motorway construction until the introduction of the Special Roads Act 1949. Early work was hampered by heavy rainfall, resulting in postponement of various heavy engineering works such as the base foundation; the result of the weather meant the original two-year plan was delayed by a further five months. Weeks after opening, the road had to close temporarily due to water causing further problems, when the base layer was damaged as a result of a rapid freeze and thaw cycle.

The bypass has undergone two separate lane-widening schemes during its existence, first in 1966 when it was widened to three lanes, then in the 1990s to expand it to four lanes in each direction. The latter upgrade was significant enough to require reconstruction of the entire route including all bridges and it is now effectively a different motorway from the one that opened in 1958.