Jingo by Terry Pratchett (see inside as to why cultural, NOT because it's from the UK)

[Karin]

3.4 stars

A small island floats up from the depths of the Circle Sea, and it isn’t long before there is the threat of war between Ankh-Morpork and the Klatchians which starts as a dispute as to who has the right to this island. The beloved watchmen become embroiled in this dispute as even the leadership of Ankh-Morpork is threatened from within.

Why did I shelve this cultural? Not because it is by a British author, but because in this book there is a great deal of both cultural clashing and cultural misunderstandings on both sides of the battle, plus a few little funny things I just don't want to spoil for you.

This is another entertaining entry in both the Disc World and the City Watch series.