Original: The first section of the motorway , and the first motorway in the country , the Preston by-pass , was built by Tarmac Construction and opened by the then Prime Minister Harold Macmillan on 5 December 1958 .
Simplified: The first section of the motorway was opened on December 5 , 1958 and was what is now known as the Preston by-pass . It was opened by Prime Minister Harold Macmillan .