Delayed for publication from last year - an annotated afterword was written since the main narrative - the account here of the ''Inside Story of the UK Jazz Explosion'' is shaped around input drawn from some 86 interviewees as referred to in the acknowledgements.

Mostly written in 2022 with the interviews taking place in 2020 and 2021 this is already an historical scene no matter how recent it still seems given how cyclical band activity is. In other words, 2024 is now, the UK jazz explosion was then. And yet a lot of people are still catching up on what to some may already be over. But already, it's not too soon, you can look back and wonder about the hows and whys of what it was all about. And this book provides some, but not by any means all, of the answers.

The bands, artists and profiles covered includes such acts as Alfa Mist, Binker and Moses, Camilla George, Emma-Jean Thackray, Ezra Collective, Kokoroko, Matthew Halsall, Nubya Garcia, Sons of Kemet, The Comet Is Coming, Yazz Ahmed and Yussef Kamaal.

The book asks how UK jazz changed from being the '''dry and unsexy' music of 'your dad,' 'my dad' and 'your grandma' to the vital politically charged inclusive sound of modern London.''

In the afterword which touches on recent global events since, André Marmot, a first time author, and who is a London based music agent, musician, promoter and label owner, writes that ''jazz is the incidental product of geopolitical conflicts and movements of people, and an attempt to respond to these wider forces.''

The shape of the book is organised after a ''12-inch promo'' introduction beginning with a ''Rye Lane Shuffle'' - Rye Lane is in Peckham, south-east London. ''You Can't Steal My Joy'' is a chapter on ''jazz, ownership and appropriation'' and certainly like the book (the clue is in the title Unapologetic Expression after all) does not shy away from hard hitting sociopolitical postulation. You Can't Steal My Joy is a title reference to a 2019 album by the subsequently 2023 Mercury winning Ezra Collective, the Mercury win for Where I'm Meant To Be, also mentioned in the Afterword, could be seen as a highwater mark in terms of outward facing wider music industry prestige of the whole movement. Chapters also touch on ''Jazz, Colonialism, Slavery and Migration''. Reference could have been made pertinently to the Zed-U featuring early Shabaka Hutchings Night Time on the Middle Passage release from 2009 as a progenitor. But Unapologetic Expression is not a book that dwells on the minutiae of inexhaustible discographical analysis although a decent one is provided and Shabaka is one of the interviewees.

The book also navigates ''jazz and postcolonial London,'' the ''Jazz Warriors and their continuum''; new media and in ''Wake (For Grenfell)'' further discussions about jazz, politics and identity - Grenfell being the terrible 14 June 2017 fire that broke out in a 24-storey block of flats in North Kensington causing 72 deaths.

A chapter on Gilles Peterson's role in the whole ''explosion'' is certainly by contrast also significant. The main thrust of the narrative is quite often shaped around a Petersonian world view navigated by the influential DJ's past and current endeavours and which have included his days in pirate radio, BBC 6 Music show, Brownswood label, awards show activities plus numerous national and international festival programming forays.

A number of the artists whose work lies at the centre of the movement were championed and sometimes signed by Peterson who talks of ''the swagger and self-confidence about this movement.''

Interviewees include most thought provokingly in the narrative Cleveland Watkiss, Binker Golding, Courtney Pine, Femi Koleoso, GP (Peterson), Hans Koller, Kerstan Mackness, Nikki Yeoh, Seb Rochford, Poppy Ajudha and Shabaka Hutchings.

It's a contentious book in quite a few ways. Think about this statement for one small instance, talking about a parallel between the culture around early bebop and 1990s gangsta rap: ''Both are musics originated by marginalised young black males that suddenly found extreme popularity among white audiences''. There's early discussion about how disrespectful the Jazz Club sketch was on BBC comedy The Fast Show and how ''as late as 2012, jazz was being openly mocked on mainstream media, not only by comedians but by professional music critics''. An argument is made that just like UK garage UK jazz was ''assassinated'' by such mockery. Later there is interesting discussion on how the Black Lives Matter movement galvanised music fans globally in a fight against racism. And the author argues that because he talked to promoters, venue owners, agents etc there is a wider viewpoint than talking only to artists. It is a very London centric book, however, and yet more significantly beyond cavilling about this in the author's words aims to be ''a meditation on modern, post-colonial Britain - in all its diversity, hypocrisy, division and flawed, self-destructive brilliance.''

The narative charts what can only be described as Tory misrule (initially in such a bad faith way with the Lib Dems) from 2010. Quoting Kareem Dayes of United Vibrations whom Marmot championed as a promoter: ''When the music and message come together it's about painting that picture of a destination we can all move towards, which is better than where we're at now''. That positivity is an important part of why this UK movement has captured the wider, global, imagination.

Such radical cultural exegesis also emphasises the role of the Total Refreshment Centre in Dalston later compiled in a Transmissions Various Artists release issued by Blue Note last year.

A fascinating book then - certainly partial and highly opinionated but nevertheless passionately argued and even better, highly readable. Stephen Graham

432 pages in hardcover. To be published on 2 May