Laycock is a Cambridge classicist who, as an aid worker, saw state-break up at first hand in Bosnia and Kosovo. That experience clearly influenced his thesis that in Britain Romanization was only skin deep; there were continuing tribal divisions, which the Roman regime in Britain exacerbated as much as reduced.
Rome introduced civil administration based on the civitates, a model originating in the self-governing Mediterranean city states. Without cities in Britain, the civitates were based on tribes making permanent tribal divisions, so local aristocracy may have continued in power.

There is evidence for inter-tribal conflict resulting from this dynamic. Was the Icenian revolt in the 1st century as much against the neighbouring Romanised Catuvellani and Trinovantes, as against the Romans?
Fire damage and the pattern of coin hoards during the 2nd and 3rd centuries on the borders of Catuvellanian territory may indicate Brigantian raids and on the northern boundary of the Trinovantes renewed Icenian raiding. Precautions against such inter-tribal conflict may have led to fortification of towns and cities in the civilian zone in the 2nd century. The pattern of fortification of small towns is informative. They were fortified on the north and west frontiers of the Catuvellanian civitas, but left unfortified in its centre.
Ammanius describes the ‘Barbarian Conspiracy’ in Northern Britain in 367-9 with Theodosius reorganising its defence. A map of coin hoards indicates turmoil in central and southern Britain. Did roving bands from southern civitates exploit the crisis further north?
In the late 4th and early 5th centuries distinct belt buckles were worn by militia from different British civitates. Laycock describes in detail these accoutrements. He compares them to the militia badges, marking the different ethnic and national groups in the multi-party conflicts in former-Yugoslavia. The belt buckles and widely distributed military triangular loop buckles within the civilian zone suggest Rome armed the civitates, which within the Empire would have been exceptional.
He notes a concentrations of villas burnt in the late 4th century north of Wansdyke in Wiltshire and Somerset. He takes this and fortifications around Silchester and Mildenhall as indicative of inter-tribal conflict involving the Dubonii, Atrebates and Durotriges. He suggests it continued after the Roman withdrawal, with the Durotriges taking over part of the former civitas of the Belgae.
Insecurity led to repeated attempts to secure promotion of a British Emperor, hoping that he would address Britain’s security problems. Such attempts denuded its defences and may have resulted ultimately in revolt of the civitates-tribes against the British diocese, which backed its last aspirant-Emperor, Constantine III.
Durotrigan territory was characterised by its large hill forts before the Conquest. They were re-used after the Roman withdrawal, with two incorporated in Wansdyke, indicating not just cultural continuity, but reversion. Wansdyke may have been built or refortified, possibly with forced labour following the late-Roman model, marking the boundary between the Durotriges and Dubonii.
The earliest employment of Anglo-Saxons is found on the borders of civitates. Thus early Anglo-Saxon sites are found at West Stow – on the boundary between the Catuvellani and Iceni – and at Dorchester–on–Thames – between the Catuvellani and Dobunii– suggesting a longue durée of inter-tribal antagonism.
The book is good read. Its thesis relies on archaeological evidence from fire damage, coin hoards and belt buckles. It may not be the whole story, but, based on the author’s personal in experience in the Balkans with resonances with late-Roman Britain, it is an interesting one.