This is an important book and I think anyone who lives in the UK and who hasn't thought about race should read it. However, I had some major issues with it. As a disclaimer: I am not black, but I'm a non-EU immigrant to the UK. I also am a member of an ethnic minority in my country of birth, I live on a low income in the UK and I'm queer.
As some of the other reviewers pointed out, Afua Hirsch has an enormous amount of privilege. Middle class upbringing, private school, Oxford, working in very competitive and eventually well paid jobs, the lot. Although I could relate to many of her discussions of Oxford and Oxbridge, that it precisely why I think this 'Oxbridge perspective' actually does a disservice to the book. I've met many people like Hirsch. In many ways, I am a person like her - someone who has some structural limitations on my life, but ultimately someone who also has the framework, the apparatus and the cultural environment of an Oxbridge education. Maybe it's what the right-wing press calls the 'Metropolitan elite' thinking. Either way, it is precisely in my comfort zone, but that is exactly why I found it limiting: I've learned very little from this book in terms of perspective or ideas. The first chapter explained exactly why it wouldn't have happened, but I would very much rather read a book written by Hirsch's husband.
Something I liked about the book and the author is the insistance that immigrants do not owe anyone to be of a particular political persuasion. This idea deserves a whole other essay, if not a book, but, in short, I have a lot of sympathy for it. However, I felt like Hirsch's own political views affected what she wrote quite a bit. I don't know what they are, but she came across as a Tory/Conservative. She painted quite a sympathetic portrait of Theresa May - probably the most positive representation of a politician in the book. However, even Hirsch's chapter on immigration completely ignored the Hostile Environment and who was responsible for it. Although it is true that Labour, or most other parties, have not been brilliant on immigrants' rights in the 2000s and have certainly been hostile in the 2010s, immigration is the one issue which cannot be brushed under the carpet of political whataboutism. Theresa May is personally responsible for what has happened to immigrants, people like me, since 2012. Atrocious family reunion rights, retroactive application of immigration law changes, a mental health crisis, countless broken lives. And, most importantly in relation to this book, the Windrush Scandal. Which is not mentioned at all. Fair enough, the book could have been written just before it became a major news story. However, the Windrush Scandal was a direct result of 2012 policies, which Hirsch, as a journalist and a reporter, has to have known about. Either she deliberately choose not to look/hear/bother about the Hostile Environment before 2016, or she is a subpar reporter. Either of these doesn't bode well for her as an author about a book about British blackness.
Another major issue with the book is that Hirsch seems to alternate between talking about black and BIPOC issues, slightly patronisingly assuming expertise on South Asian, Eastern European and other immigration issues. At the same time, there are quite a few parts of the Black community and experience she doesn't talk about. All the Muslims in this book are South Asian - even though a large number of Black British people are Muslim. She doesn't talk much about gender, or sexuality, within the Black community, and the effects those have on identity and belonging in the Black community (she mentions queerness in passing in one sentence - that would have been a very interesting and much needed CHAPTER!). Even though the book is supposedly about Black Britishness, it is primarily if not exclusively about England - she mentions that the situation is different in Scotland, Wales and Northern Ireland, but she doesn't include any stories or interviews to highlight some of those issues. Is Black Britishness in Scotland different? How? Why? Basically, large parts of the book don't seem relevant, whereas many key issues are not covered.
Finally, some of her generalised references to passing subjects are subpar. For example, she talks a lot about history, but some of the specifics she mentions are dodgy. She claims that thousands of Africans were brought to England during the reign of Elizabeth I, which is simply not true, even though she had previously mentioned the work of Miranda Kauffman (Black Tudors), which clearly shows that there were around 300 documented Africans in Tudor and early Stuart England. I agree with her larger argument - there were many people from different cultures in early modern England and early modern England was responsible for the beginnings of the slave trade - but sloppy errors like this actually reduce the credibility of what she is saying more broadly. I happen to know about this specific example, but how many other instances are there where Hirsch makes a passing remark and the reader takes her at her word?
Overall, a good and important book, but there are several caveats to keep in mind.