I’ve written several times (most recently here) about the phenomenon of American characters in British novels using British expressions, seemingly because the writer didn’t realize they were British expressions. I’ve just read a book by an American novelist, with American characters, where Britishisms abound.
The book is The Plot, the author Jean Hanff Korelitz. In my view, some of the examples are nothing more than NOOBs — that is, British words and expressions that have become popular in the U.S., and hence an American character might use. Others are flat-out Britishisms that I’ve rarely or ever heard here. I’ll list them in order, from the most common NOOBs to the least likely. Examples in quotation marks are a character speaking, and the others are the author’s narration.
- in the fullness of time…
- “You were spot-on with all that.”
- … she straightaway found a job…
- “Would it kill you to do an avocado toast?” (That’s “do” in the sense of a restaurant offering a dish.)
- “who knows what else this Dianna Parker got up to?” (Instead of “got up to,” Americans would say “was up to” or “was involved with.)
- the guy … supported the Red Sox… (“Support” meaning root for or be a fan of.)
- Maybe the punters out there believed novels followed a visit from the muse …
- Jake opted not to correct this remarkable statement in any of the ways he might have done. (An American would end the sentence with “he might have.” This verb construction is actually one of the White Whales of the blog — something I have been hoping in vain to observe an American using. Until now.)
I mentioned that the author, Jean Korelitz, is American. But she studied at the University of Cambridge in the 1980s, and since 1987 has been married to the Irish poet Paul Muldoon. So she comes by her Britishisms rightfully. But that doesn’t mean that her editor shouldn’t have flagged “punters” or “might have done.”
notoneoffbritishisms.com 
I’m a Canadian, born and raised in Toronto, and I’ve spent only about two weeks of my (now long) life in the UK, yet all the quotes you give as being British strike me as normal (except perhaps for punter). Could it be they’re commonly used in some parts of North America (or possibly in Canada but not the US)?
Canada is a special case, to be sure. I don’t have a very strong sense of the extent to which Canadians use Britishisms, except for pronouncing “organization” “organ-eye-zation” and “process” “proh-cess.” The Corpus of Global Web-Based English (https://www.english-corpora.org/glowbe/) lets you search for a word or phrase and see its relative use in a range of English-speaking countries in the early 2010s. I tried “straightaway” and it showed 3-4 times more frequency in Britain than in U.S. *or* Canada.
Most of those are not fit for use by an American. Here is my take:
Fullness of time is venerable and honorable in American.
Spot-on is inexcusable by an American yet, sadly, its use is no longer pinpoint in nature.
Straightaway is also moving briskly into American.
“Let’s do lunch” is an American taste of your example for “do,” but qualitatively different. My father– from Georgia, USA– has for many years used “do” with food, though, so perhaps there is a US precedent.
“Got up to” raises eyebrows when said by an American.
I have to root against any American who uses the Frenchism “supported” in relation to sports teams.
I’m tempted to punt on punter, but it’s too easy to block: There is little chance of this term making it into American simply because it already has a very common different meaning in American.
As an American, the author might have done the right thing by avoiding that usage.
A reminder to those who have not read or do not remember my personal bias: My (only half-joking) position on NOOBs is that they are not/not welcome in American. Please don’t accuse me of being close minded about this, as I am preemptively declaring that I am close minded.
What is your mind close to? I the UK we’d say closed minded.
I can’t recall any Briton using straightaway. Right away is quite common in my experience. The only time I’ve ever heard or read straightaway in a car racing context (straight in British English).
In Britain we would use ” straight away” and think “straightaway” was an Americanism.
Interesting! Calls for further research.
I agree. I think the two-word version is the expression meaning “immediately” and the one word version is a term of art in motor sports.
to clarify my comment above: “straightaway” – one word – is a term of art in American motor sports
The latest version of Chambers dictionary give both. Straightaway meaning straight forward and straight away meaning immediately. Neither are marked as North American. From that, I’d say in English English, the space would be there.
The word order is wrong in British English as well: “… she found a job straight away …”.
American living in Britain for 7 years here. The “fullness of times” phrase is used regularly by the mormons (Utah), but anecdotally I’ve not heard it used in the UK.
As for the rest of them, I guess I’ve gotten so used to them I’d also have a hard time separating them from American English- even including “straightaway.”
Very interesting post, I love these small differences in the use of language.
As an American I agree mostly with what David Ballard said above on usage. I have however begun occasionally using constructions like “might have done” as it seems more “complete” and perhaps is an addictive earworm for anyone having heard the Britishism. We do already use that construction for closely related phrases like “might have gone”, for example, so it isn’t much of a stretch. In the opposite direction I always smile when I hear people in the northern tier Great Lakes area say things like “Would you like to go with?” –meaning go along in a car or whatever– completely dropping the object. And they seldom realize they are doing it and will sometimes deny it. 🙂
Another doddering old Brit and, like others, only aware of, “straightaway” in the US motor racing context. The examples given in the post look downright odd and sound a bit jarring to my inner ear.