R. F. Delderfield was a UK novelist. <em>The Dreaming Suburb</em> was published in 1958 and is part of a two-novel series called <em>The Avenue</em>. There is a reference to the 1931 election. The character, Jim Carver, was a Socialist and therefore supported the Labour party. We read:

<em>Jim Carver was not unduly cast down by the Labour landslide in October that year, and the virtual collapse of the party that was to have to ushered in the Millennium.</em>

In the UK, does "Labour landslide," without further explanation, mean that the Labour party <em>lost</em>?

In the United States, a phrase like "an Eisenhower landslide" would mean that Eisenhower <em>won</em>; a "Democratic landslide" would mean that the Democratic party <em>won</em>. To use "landslide" to refer to a loss, you would need to say so. In 1964, Republican Barry Goldwater ran against Democrat Lyndon B. Johnson. We would need to say "there was a Republican landslide loss" or "the Republicans lost by a landslide," or "the Republicans lost in a landslide," but we could just say "there was a Democratic landslide."