Is "Spate of " singular?

Question

Which of the following is correct?

A recent spate of attacks have

or

A recent spate of attacks has

Answer 1

"Spate" is a singular collective noun.

A spate of attacks has ...

Treat it similarly to the following, for example:

A gang of children is over there; a clump of bushes is in the middle of the garden; a murder of crows is very loud; etc.

Answer 2

The problem is which noun the verb should agree with - the singular, countable noun ('spate') or the plural noun ('attacks').

Some speakers prefer to prioritise morphosyntactic logic (e.g. 'spate' requires a singular verb). Others prefer to allow synesis (also known as notional agreement or notional concord) – a grammatical construction in which agreement or reference is according to sense rather than strict syntax (http://www.merriam-webster.com/dictionary/synesis). Effectively, synesis is an agreement of words with the sense, instead of the morphosyntactic form (https://en.wikipedia.org/wiki/Synesis).

Both usages given in the OP are widespread and since both are clear (and the goal after all is clarity) probably it's best not to worry too much!

For myself, it depends whether I am wanting to talk about the collective entity (singular) or its constituent parts (plural):

• A recent spate of attacks has lead to fewer late night parties.
• A recent spate of attacks were (all) perpetrated by the same gang.