This article is from the alt.usage.english FAQ, by Mark Israel email@example.com with numerous contributions by others.
Use of a plural verb after a singular noun denoting a group of
persons (known as a noun of multitude) is commoner in the U.K. than
in the U.S. Fowler wrote: ""The Cabinet "is" divided" is better,
because in the order of thought a whole must precede division; and
"The Cabinet "are" agreed" is better, because it takes two or more