One of the best books about Dunkirk is a recent one: "Dunkirk; Fight to the Last Man" Hugh Sebag-Montefiore ISBN 978-0-141-02437-0 Very scholarly work that covers most of the detail.

One of the bits which is missing from all histories about the Dunkirk evacuation is obvious to the military eye: none of the commanders involved has been indiscreet enough to mention the actual staff plan for the evacuation - ie which units were prioritised for evacuation (initially, of course, they only thought they'd save a few thousand) and which ones were assumed to be lost (not counting the sacrificial perimeter rearguards). By looking at the personal accounts, its possible to deduce what happened: the intact line infantry units were directed to the town and the Mole for immediate evacuation, followed by major formed divisional units, such as gun batteries and engineer squadrons. The odds-and-sods divisional and lines of communication troops, straggling back in small units and groups, were directed to the beaches four or five miles away. This reflects what happened in Greece, Crete and Norwayicon, where brutal-but-logical decisions had to be taken about who to save and who to abandon to captivity.

This evacuation plan is reflected in the profile of the accounts: most of the "beach & small boats" accounts come from RASC, Signals, unit echelon troops, etc. This is also reflected in anecdotes that refer to lack of small arms or acquisition of small arms: the line infantry units mostly marched to the Mole with their full equipment - as you'd expect with infantry. The support troops, by contrast, had been heavily dependent upon motor transport. Anyone who has served can probably confirm that the back of a flaggies' wagon is more like a hamster nest of cooking equipment and cushty sleeping arrangements - with rifles usually buried somewhere at the bottom. Many accounts report the loss of rifles when transport was either shot up or abandoned. Many other reports also tell of disarmed men retrieving arms from such vehicles.