There has/have been a series of accidents...

0has - it links to 'a series'.0-

1blockquote

01cite10nona the brit12cite10has - it links to 'a series'.12br
12blockquote

10Nona,02br
00I think we might have a BrE/AmE difference here. When I read the original post my immediate reaction was to say that "There 01b00have02b00 been 01u00a series of car accidents02u

0I found several examples using plural verbs through Google Book Search. For example: 02br
02br
001. And01b00 there01font00 are02font00 a series of 01font00decisions02font02b00, based on what principle we are... 02br
002. 01b00There 01font

1blockquote

01cite10Viceidol12cite10I found several examples using plural verbs through Google Book Search. For example: 12br
12br
101. And11b10 there11font10 are12font10 a series of 11font10decisions12font12b10, based on what pr

0Could be a difference in different versions of English (or it could be just me) but all of those examples grate horribly to me.02br
02br
00It might be to do with how we view the word 'series'.02br
02br
00Would you say02br
02br
00A bunch of flowers is in the vase.02br
02br
00or02br
02br
00A bunch

there has not been openings
there have been no openings

Good news! I have THE answer! Bryan Garner (the "American Henry Fowler") says "series" is ordinarily singular as in "the series is popular," BUT it is also a noun of multitude as in "a series of things," which takes a plural verb.

Yes - it is a difference between BritE and AmE and as such, both are correct.
In American English it would be, "There have been a series of accidents".
In British English it would be, "There has been a series of accidents".
Check for whom you are writing or proofreading.

Hi, Anon.
You seem to agree with Nona the Brit!

Do I assume correctly that the British would NEVER say "A series of X's are etc."?

There has been a series of car accidents at the crossing.