The World's War: Forgotten Soldiers of Empire, BBC Two

We call it the First World War, but in Western Europe at least, most of the scrutiny is confined to what happened to Britain, France and Germany (with a side order of Russia) from 1914-18.

Beginning with the revelation that the first shot fired by the British Army after the declaration of war in August 1914 was from an African soldier of the British West African Frontier Force in an attack on German forces in Togoland, Olusoga swept across the battlefields of France and Belgium, but also probed skilfully into the mysteries of the imperial mindset. This was crammed with weird notions about race and fighting spirit (it was a place where "the madness of war is overlaid with the craziness of racial prejudice," as Olusoga put it).

We learned how the British Army in India was keen on the "Theory of the Martial Races", and such experts as Lt Col JWB Merewether enumerated the attributes of the various Indian peoples in the way he might have assessed racehorses or bloodhounds. The Jats (from the Punjab) were a tough and durable "thoroughbred race", the Pathans were "handsome" and "athletic", and the Gurkhas were cheery, adaptable and friendly. Naturally all of them would need the firm guiding hand of white British officers (colonial prisoners held by the Germans at Zossen, pictured above).

At the start of the war, the British were desperately short of professional fighting men, and the contribution of the Indian corps proved critical in stemming the German onslaught at Ypres, though photographs of the Indians enduring the freakishly cold winter of 1914 were pitiful to behold. They also came close to achieving a potentially war-winning breakthrough at Neuve Chapelle. Olusoga had unearthed a cache of letters written by the troops, in which they used imagery of their former faraway rural life to describe this hideous technological carnage - "men are dying like maggots... none can count them", "the corpses cover the country like sheaves of harvested corn." By the end of 1915, they'd suffered so many casualties and lost so many officers that they were transferred to the Middle East.

Meanwhile the French were somewhat schizophrenic about their own colonial troops (many of them from West Africa, grouped under the collective heading of "tirailleurs Sénégalais"). Though the so-called "Force Noire" performed such feats as helping to recapture the Douaumont fort at Verdun, and were fêted with jingoistic fervour by the French press ("un Noir vaut deux Boches"), the French establishment was disturbed by lingering folk myths depicting the Africans as priapic savages liable to run amok in the jardins of the bourgeoisie. The soldiers were therefore taught only a minimalist, baby-talk French, and were groomed to behave like "the loyal simpleton soldier", as historian Alison Fell put it (a Senegalese tirailleur, pictured above).

As for the Germans, they were deeply pissed off that the Anglo-French navies had cut off access to their own overseas colonies, and responded with brutish propaganda about how their enemies were employing ape-men to win the war. German cartoons portrayed John Bull as a grotesque Negroid caricature with a ring through his nose, while the Africans fighting for the French were turned into half-naked cannibals. And this was long before anybody had heard of Joseph Goebbels. It was extraordinary stuff, rendered even more powerful by the gently regretful tone of Olusoga's delivery.