M55 motorway meet junction 4, where the motorway ends and becomes the A5230. The western part of the M55, and the first few hundred metres of the A5230, occupy the route of the old Blackpool Branch railway line. The first motorway constructed in Great Britain was the M6 Preston Bypass, opened in 1958. This ran from the current M6 junction 29 to the M55 junction 1. It was built as a two-lane route. In 1965 the M6 was extended north from what is the current day junction 32 to meet the Lancaster Bypass, and the M6 junction was rebuilt to its current
M6 motorway to the edge of the Lake District with a short stretch within the national park boundaries and then passes Carlisle on its way to Gretna, before the motorway becomes the A74(M) a few hundred metres (yards) short of the Scottish border. The first section of the motorway and the first motorway in the country was the Preston By-pass. It was built by Tarmac Construction and opened by the Prime Minister Harold Macmillan on 5 December 1958. In January 1959 the Preston by-pass was closed because of rapid surface deterioration over a stretch of "due to water freezing and then thawing".