Calling all armchair generals! Boudica's Last Stand.

[Nathan Ross]

The point I am trying to make is that armies can move far faster than 18 miles a day on a long march when it is necessary

Another example would be Henry III's march with infantry and cavalry from Nottingham via Grantham, Aylesbury and Kingston to break the siege of Rochester in April 1264 - a distance of c.176 miles covered in eight days, at around 22 miles a day.

my theory does not rely on the Iceni / Trinovantes in a race to reach London first

I'm increasingly coming to agree with you on that, although perhaps for the opposite reason!

As I now see it, Tacitus does not tell us that the Britons advanced immediately on London after defeating Cerialis, and had they done so it would have suggested a degree of planning and intention that I doubt they possessed at first. The conquest of Colchester and the destruction of a Roman relief force would have given Boudica and her followers considerable renown, raised their ambitions, and expanded what had been a relatively local revolt into a much larger uprising.

I'm not convinced by the idea of the Iceni etc returning home after Colchester, although I know we've discussed this before. Letting the rebellion dissipate at that point would seem a mistake. London was undefended and had large supplies of grain, so heading there sooner or later would be an obvious next objective. And it does seem that the Britons did not expect that Paulinus could move his troops quickly enough to oppose them, as he was supposedly tied up in North Wales.

Paulinus 'saved the province with rapid movement', as T says in Agricola. So it was perhaps while the Iceni and Trinovantes were gathering allies and deciding plans for the next move that he got his army down to London.