Henry VIII: Dressed to kill, Tower of London, London

Even before you reach the top of the wooden staircase that mounts up and up and up the outside of William the Conqueror's White Tower, the structure by which the Tower of London is most readily identified, you begin to hear more than a bit of hullabaloo. Then, when you push through the swing doors, it hits you full in the face. This is the All-Action-Hero Henry VIII show – military man, sportsman, icon of then and now! A bit over the top? You bet!

The first glimpse of him you get, he's sitting astride a white charger, rearing over you, in top-to-toe dress armour, pent inside a huge glass display case set against a light box that flashes white, then blue, then white again. Curious, the horses in this show. They are all white, like strange, ice-stiffened soft toys. The presentation brings together several beguiling elements of our current civilisation: a Selfridges window-display; a CNN newsflash; the slinky glitter of the catwalk.

Next to Henry on horseback, there's a bit of filmic virtual reality – huge men in mortal combat; bigger, much more manly men than you could ever hope to be. And to help the deliriously excitable atmosphere along, there are tremendous noises coming from everywhere – the rake and clash of sword on sword, the earthquake-like trembling of horses' hooves. And then, of course, to top it all, there is the customary racket of schoolkids when they mooch around in packs, munching and jawing, pounding the bare boards of this ancient hall, which used to display part of the Royal Armoury Museum, now displaced to Leeds.

He spent so much money on warfare, this man – close to the equivalent of £1bn in 2009 terms. Often, it was not too well spent. How many gains did he make for all that campaigning overseas? But the armour, the swords, the jousting poles, these divine arquebuses, all this gorgeous canonry!

Yes, it has to be said that all this money and all this bought-in European expertise helped him to amass some marvellous playthings, and many of them we won't have seen before because they are from museums overseas. What is more, we quickly begin to learn all the arcane, toothsome terminology of armoury, and so many of these words are so delicious to roll around the tongue: the nine-plate "crinet" that would have protected the horse's neck, the vambraces, the crossed ragged staves, the parade armet...

But the problem with this show is that it's too distortingly narrow in its focus. In trying to turn Henry into no-holds-barred action man, it loses sight altogether of most other aspects of his life and his reign. Religion? Forget it. Wife problems? What were their names? By making him larger than life, you turn him into a grotesque, small-scale caricature of his complicated self. The film on show at the end tells it all: it's just a messy bringing-together of contemporary images, clips from feature films and other bits and pieces, to the ridiculous accompaniment of a bit of 1970s-style glam-rock noise. Who cares where truth ends and fantasy begins?

Still, by the end – and the show goes on for two and a bit floors – I'm thirsting to own something of my own, so when I spot the full-size foot combat armour in the shop, a snip at a mere £4,209, I get into conversation with the sales assistant. No, she doesn't work here, not exactly; she's in marketing, she tells me, trying to distance herself from the mugs she's busy with, but as far as she knows, they have sold a few. Just a few years back, there was a man who wanted two for his restaurant in Italy. So I ask the lad on the till. Not since he's been there, he says; something to do with transportation difficulties, perhaps. All the same, I put in a call to the wife: muzzle the Bedlington, dear; enlarge the door frame.

To 17 January 2010 ( www.hrp.org.uk/toweroflondon )