What is an English word for the events that are part of a larger event?

Solution 1:

You could use portions but for your particular example sentence I like

facets

The fun thing about this is that you can imagine a geometric solid with lots of sides or facets, for example a 12-sided die. Turn the die to a different face, and you get a different episode in the Brexit saga. (Episodes would be linear -- but you can shuffle them up to assign them to a side of the die.)

facet (Oxford)

1 One side of something many-sided, especially of a cut gem.

‘a blue and green jewel that shines from a million facets’

2A particular aspect or feature of something.

‘a philosophy that extends to all facets of the business’