Calling all armchair generals! Boudica's Last Stand.

[MonsGraupius]

I am not an academic and so do not consider myself qualified to argue or comment on the sources and various translations.  I am an interested amateur.  I am, however, a retired military professional educated at Staff College and with practical experience of warfighting and other operations over 41 years and so feel qualified to discuss the possible (conjectural) military operations.  What we probably need is a latter day Tony Clunn to find the battlefield.

William Roy wasn't an academic, just a mere soldier. But if he had the aerial photos showing the line of Roman forts going up toward the coast in NE Scotland and the modern database of dated artefacts, we wouldn't have had centuries of academics randomly picking their favourite hill in Tayside on which to site Mons Graupius.

I take several of your points.  However, you keep saying things like "beggars military logic" without actually explaining your reasoning in terms of warfighting. 

For example why with his main forces west and north does he go away from them?

I have, but it's obviously got buried. Suetonius gets to London and we are then told that he leaves and the populace are "overwhelmed" in London. Given that London bridge goes from the settlement of London over the Thames, it is impossible to overwhelm people in London, unless they were caught out by surprise, or the bridge was taken down. Given they knew Boudica was on the war path, it appears the bridge was taken down.

The Thames has very few fording points, and those it does have are difficult. They are so difficult, that the Anglo Saxons write that Wallingford was the lowest fording point. However, there may have been half a dozen places, where in the right conditions of river and tide, that a crossing could be made with difficulty. But all these are quite low down the Thames roughly London bridge to Chertsey. Being so difficult, they are relatively easy to defend. The ford itself can be made impassible and once that is done, a small force can prevent engineers working to make it passable.

So, because people were "overwhelmed" in London, it appears London Bridge is taken down by Suetonius, and because Catus flees south (to Gaul) we know that is the direction of safety for the Romans ... which means that people fled over London bridge to the south. That orientates the whole battlefield, putting the Thames as the front line when Boudica ransacks London, with London bridge down to stop her advancing.

We know from the text, that Suetonius DELAYS, That he PREPARES, that he is looking for a "SEAT OF WAR", that he does not want to be "RASH" like Cerialis. Everything in the text tells us that Suetonius makes his way to a place where he can regroup and prepare to fight with Boudica.

If Suetonius heads north ... he is crazy. Because the whole of the east coast of Britain from the Thames to the wash is now in Boudican control. He cannot supply his army from the east, nor with London under Boudican control, from the south across the Thames. We know he was being harassed when he came to London

Suetonius, however, with wonderful resolution, marched amidst a hostile population to Londinium

So, we know he does not have good control over the area from north Wales to London. We also know the SW is problematic as Postumus is unable to leave that area.

So, Suetonius is very short on secure lines of supply. If he heads north, he is almost totally cut off from any supply lines, except those from the west, which in turn can only be supplied from the south coast or perhaps the Severn estuary area. And, so the military logic, is that he needs to keep control over the supply lines which means holding the Thames to prevent boudica taking over the south of England and maintaining an army to secure supply lines from the S.Coast up to Calleva ... to where ever Suetonius has his "seat of war" (if not Calleva)

I agree that SP wants to buy time.  Crossing a river, even by a bridge, with 5-6,000 men, equipment and baggage is slow (even now) and since SP takes civilians with him, even slower.  If SP, as you seem now to indicate, fought the "final" battle in the Chilterns he must have taken his army there somehow (or are you now saying it was there all the time and there really was a "cavalry dash"?) 

I am suggesting that Suetonius heads somewhere south of the Thames, using that as a defensive barrier, probably to Calleva, where he spends a month or two regrouping, resupply and probably re-equiping, so that, with his much smaller force, he is ready to take the offensive. So, no "rash" dash into the arms of boudica. Instead a carefully planned campaign forcing boudica to come to Suetonius, when Suetonius is ready, and at a battlefield of Suetonius' choosing. In other words, Suetonius is ensuring everything but number of troops is stacked in his advantage. And clearly, he needs that to pull off such a dramatic win.

Are you saying that going south and placing a river and the enemy between you and your own reserves is "logical"?  If SP does not have the strength to hold London then he logically does not have the strength to carry out one of the most difficult military operations - an opposed assault river crossing.

The SE of England is held by a Belgae Gaulish elite who are generally pro-Roman. They will not like Boudica any more than the Romans and so, Suetonius is crossing the Thames into friendly territory.

However, once across the Thames, whilst he can easily hold it against Boudica, he doesn't have the forces to force a crossing. Which is why he has to go up to where it is relatively easily crossable upstream of Goring. (E.g. at Dorchester)

I also agree that crossing the Thames gives him a defensible line but only if he intends to stay and defend it.  Military logic (and tactical/strategic doctrine that I have studied at Staff College and applied for over 40 years) is that an undefended obstacle is no obstacle.  So unless SP defends it the enemy will cross it unopposed by whatever means available. 

He needs to get the SE Belgae tribes to come on side and agree to man the Thames defensive line. As that is defending their own land against the the ancient enemy of the Marauding Iceni, that won't take a lot of persuasion. Once the Thames is secure, Suetonius can move west to Calleva, from where he is able to start preparing to cross the Thames and begin to threaten Boudica with a march NE along the bottom of the Chilterns, where he threatens to cut off St.Albans.

I am pretty sure the Ancient Britons had crossed rivers, including the Thames, before the Romans put up their bridges.

No defensive line is impenetrable ... it's a question of what advantage it gives the defenders. Anyone with the ability to climb, could scale Hadrian's wall ... and I'm sure many did. But that doesn't stop it being a defensive wall.

If you want to know whether the Thames was crossable, might I suggest that we meet on the Tay and let me show you what it is likely crossing a river the size of the Thames, in its natural state. To be fair, I know it is currently not crossable ... (checking today) actually it's quite low right now, although twice the flow that I usually do it ... so I can't be sure it isn't crossable, but it was terrifying the last four times I've done it, and I am the only person to try it for about 30 years, and it's slowly degrading, so I may be the last. But, perhaps with you holding onto me for dear life it will be easier? (In theory it is easier with multiple people ...but for some reason, I've not found anyone to accompany me)

But, Ancient Britons would be used to crossing rivers, but crossing in armour where you are bound to die if you slip or fall and when under a hail of arrows, presumably with all kinds of debris being thrown in the river to push you off the ford, with a ford wrecked ... so having to rebuild the ford, in the middle of a river, under fire, with trees floating past. I do not know how they did it.

  Even if he does defend it with his small force military logic on the other side (please do not forget the enemy) is that fixing him in place with part of the force then outflanking him at some unopposed point is a fairly obvious ploy. 

I have not seen your proposed time line for this campaign so please supply (or reiterate) your version so that we can discuss military logic in context.

It was so long that Tacitus issues a mild rebuke about "delay":

he prepared to break off delay and fight a battle

That suggests that before the battle, he came under huge political pressure to stop his preparations and instead do a Cerialis and head rashly into battle with Boudica. We are told the Britons failed to plant harvests because of the uprising, which indicates it occurred before March. If we allow a month for Colchester and the defeat of the Ninth, that brings us to April, although the roads may not have suitable until May. Also Suetonius is already fighting in Wales, so it has to be after the campaigning season starts. So, I'd suggest May is probably when London and then St.Albans get sacked. Suetonius is going to want to have finished the Boudican Campaign, before autumn river levels or October. It's ~150 miles from Thames to Norwich. Which in a hard fought campaign might take 3 months. So, he's not going to want to start a campaign after July. If you factor in time to negotiate deals with the SE Belgae tribes, to bribe a few others, to send messengers to get and then deliverer new supplies, then from a potential sacking of London in May, he has up to two months to prepare.

Given he was under pressure to get off his Rs and "end delay", I think he may have been trying to start the campaign in the next spring, but got pressured into a very pressured start in July. That gives him a few weeks to fortify and man the Thames with Axillaries, and then may six weeks to arrange supplies, equipment, men. Which if he left his supply wagon in Wales, is not a lot of time. How long does it take to make a wagon?

Glibly quoting "military logic" without explaining it in the context of warfighting is not helpful to your argument and indeed weakens it.  When citing military logic you really should first state your assumptions:
What is SP's ultimate aim and outline plan of campaign?

His first aim is to stop Boudica at the Thames, for which he has to sacrifice London and St.Albans (probably got some very harsh words from the emperor on that).

He then has to gain control over the SE of England, which is relatively easy as they are pro-Roman and don't want an Iceni hoard coming into their land.

Having stopped Boudica, and secured his supply lines from Gaul and the friendly SE, he then has to secure the upper parts of the Thames which are vulnerable to being crossed. Hence his move to Calleva. This also puts pressure on the more westerly tribes who might have been considering joining Boudica. With this threat and perhaps a lot of money, he then has control of the country from the Thames to the Severn and "friendly" tribes up into the midlands. This prevents the British tribes joining together en masse with the Iceni.

Suetonius doesn't have the numbers to fight a long drawn out campaign as he does not have the troops to protect long supply lines. So, he has to force boudica to come to hi. So from Calleva, he then needs to pressure Boudica into a battle of his place and time of choosing.

Crossing the Thames somewhere near Dorchester, he then moves NE so that those Iceni holding London and St.Albans, now risk being caught between Suetonius and the Thames (held by friendly forces).

They either have to withdraw or fight ... and Suetonius has chosen the ideal battlefield on some valley on the Chilterns, where, the Iceni (from flat Norfolk) will have no idea how to fight, and where he can use the terrain to protect his smaller force from the much larger Boudican army ... which is going to be tired, squabbling and wanting to get back home, after the long journey to fight Suetonius

I have spent many long hours on this process at Staff College, in exercises and on operations and as an introduction you might like to read this Australian pamphlet (228 pages).  The tactical version is shorter.  I do not have a link to the UK version but though not identical it is similar https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiRp52T6Zb6AhXIa8AKHbP6BpwQFnoECAkQAQ&url=https%3A%2F%2Ftheforge.defence.gov.au%2Fsites%2Fdefault%2Ffiles%2Fadfp_5.0.1_joint_military_appreciation_process_ed2_al3_1.pdf&usg=AOvVaw2V8VxurP3T0c4RTq1l-W0u 

They don't mention rivers. They don't mention fords. The only patrols are boats and aircraft patrolling.

They do mention logistics, but the only section that mentions it in the title is this one which gives us a flavour of it all:

J4—Logistics. J4 staff coordinate all logistic advice, formulate logistic plans and monitor their execution. The J4 is the principal adviser across the broadest definition of logistics, which includes movements. The J4 branch sets priorities for the overall logistics effort and movements within the JFAO, and is the interface with assigned logistics FE. The J4 branch also sets the logistics, medical and health service support policy ensuring this is met throughout the operation. The J4 branch is usually well-staffed and could also contain J1/4 coordination, J1, J4 supply, J4 equipment support and J4 medical.

I do see this:

Particular care should be taken with quantitative analysis when examining consequences that are intangible or difficult to quantify regarding issues such as the environment, safety or reputation.