Original: The last time that the Conservatives won the most seats in Scotland, was in the general election of 1955. From the early 1960s that role was taken by the Labor Party and the Scottish Conservatives went into a state of decline, which culminated in the loss of all Scottish Conservative seats in 1997.
Simplified: At the 1987 General Election, the Conservatives were reduced from 21 to 10 Scottish seats, and the party lost all of its Scottish seats in 1997.