In popular elections a majority of the ballots cast, this is really very basic stuff, results usually in a majority.
Sometimes, although rarely in a field with more than more two candidates, you might get an absolute majority - i.e. 50% + - but usually, in almost every election in the UK, you get someone who has a simple majority, otherwise commonly known as a popular majority.
Driving the point home - this means that they have received more ballots from those who have voted than anyone else in the field - i.e. you are the most popular therefore you have a popular majority.
The Tories have a popular majority.
You may not like it, I certainly don't like it but that is the reality.
If Labour ignores that, then they are fools.