Seduced by a scarlet fever

Redcoat is not a history, but rather a portrait of the British Army between the Seven Years War (1756-63) and the Indian Mutiny (1857-9) - a century during which the British infantryman marched, camped and fought in a red uniform coat.

Though khaki began to come in during the Mutiny, the Army remained much attached to its red coat, not least, perhaps, because of its fabulous pulling-power. Richard Holmes quotes Mayhew's study of the London poor, which concludes that nursemaids, in particular, were liable to succumb to what he called "the scarlet fever".

Throughout the period the infantryman was armed with Brown Bess, introduced in the 1720s and last used in the Mutiny. The best infantry flintlock musket in Europe, it threw a lead ball three-quarters of an inch in diameter. In good conditions a well-trained soldier could get off four rounds a minute, but would be unlikely to hit his target at more than 80 yards range.

Wellington famously referred to the rank and file as "the scum of the earth". He was perhaps too harsh: Richard Holmes calculates that only 10 per cent of his army was incorrigibly criminal, though almost all possessed, according to Private Thomas Pococke of the 71st, "an inordinate desire for spirits of any kind", and would "sacrifice their life and safety for drink".

Nevertheless, when well-led and well-trained, it was the infantry, disciplined, resolute and steadfast - "There we unflinchingly stood, and there we unflinchingly fell," wrote Captain Leslie, describing the 29th at the bloodbath of Albuera in 1811 - which was responsible for the army's victories.

The cavalry, far more showy, was inclined to be overcome by the excitement of the chase: as happened, for instance, when the Union Brigade made its ill-fated charge at Waterloo. "Old Will was a fox-hunter before he became a cavalryman," reflected Henry Havelock in 1848, after his brother had led the 14th Light Dragoons into a nullah full of Sikh infantry.

The foxhunting attitude was still present in the Western Desert in 1942, as readers of Keith Douglas's Alamein to Zem Zem will recall. In both foot and horse regiments promotion was strictly according to seniority, but could also be purchased: though this may seem a totally bizarre arrangement, it did have its advantages. Wealth and incompetence are not necessarily synonymous, and rapid advancement could be advantageous to the service: Wellington was lieutenant colonel of the 33rd at 25; nowadays a very capable officer would have to wait at least 10 years longer.

Richard Holmes obviously has a deep love of his subject, and writes of it with an infectious enthusiasm which is impossible to resist. Sensibly, he has made great use of contemporary testimonies - letters, diaries, memoirs and autobiographies - which bring the narrative to life, while one pleasingly demonstrates the enduring nature of Army traditions. The manner in which Alexander Somerville, who joined the Greys in 1831, had to fold his blankets, sheets and rug for inspection seems to be exactly the same as that employed by national servicemen in the Royal Artillery in the 1950s.

Holmes crams information into the book until the binding begins to creak, often allowing his fascination with minor events or subjects to lead him away from his main argument. But the reader is delighted to follow him when, for example, he interrupts a discourse on morale and leadership with a glance at Jemmy, the wire-haired terrier of the 8th Hussars, who was slightly wounded when he charged with the Light Brigade, had a special collar to take the four bars of his Crimea medal, gained another clasp during the Mutiny, and was eventually lost in 1858 when swimming the river Chanbal.

Readers of Bernard Cornwell's novels about the light infantry of this period, or Allan Mallinson's about the cavalry, will find Redcoat an indispensable companion; those curious as to how the British Army ended with a record of wins for which any Premier League manager would give his eyes, let alone his eye-teeth, will discover some explanation for its success here; and, finally, anyone interested in reading a vivid, colourful and absorbing account of the past should look no further than Richard Holmes's work.