Blenheim: battle for Europe by Charles Spencer

This 13 August is the tercentenary of the Battle of Blenheim, the Duke of Marlborough's famous victory over the armies of Louis XIV, and the first great English armed exploit on the Continent since Agincourt. Charles Spencer thinks the battle and its victor have fallen into undeserved obscurity and sets out here to put the record straight.

In 1704, John Churchill, Duke of Marlborough, deceived the French into thinking he would campaign in Belgium, Alsace or the Moselle, then switched fronts and marched 250 miles to the Danube. Marlborough and his great comrade, Eugene of Savoy, led an army of 52,000 against a Franco-Bavarian force of 60,000, commanded by Marshal Tallard. In a day-long battle where the issue was in doubt until about 4pm, they finally routed the enemy, taking more than 10,000 prisoners and inflicting more than 30,000 casualties for the loss of around 10,000. It was a messy, slaughterous affair that severely rattled Louis XIV but did nothing to halt the War of Spanish Succession, destined to last another eight years, which ranged England, Holland and the Austrian Empire against France, Spain and Bavaria.

Marlborough's victory was due to a number of disparate factors: poor French intelligence; low levels of cooperation between the French and their allies; the inflexibility of the French front - its units in Blenheim village were cooped up and unable to come to the aid of the centre - plus the inability of the pistol-firing French cavalry to deal with the impact of the sabre-wielding English horsemen. Most of all, Marlborough won because of Tallard's incompetence. The Marshal failed to contest the Anglo-Austrian passage of the Nebel (a tributary of the Danube) and fatuously waited for his foe to form up on the other side before giving battle. As Spencer admits, if Tallard had disputed the crossing - as any half-decent commander would have done - Marlborough could not have won.

Spencer provides a workmanlike and efficient, though rather unexciting, account of the battle. Most of all, though, he is implicitly making the case for Marlborough as a great captain. Nobody who heard Earl Spencer's famous speech in memory of his sister Diana in Westminster Abbey could doubt his commitment and advocacy skills, were they properly brought into focus. But Spencer seems to think the arguments for Marlborough's military status speak for themselves. He never considers the more powerful rebuttals that consign the duke to the second rank.

In the first place, if you want to argue for Marlborough, you have to zero in on his victory at Ramillies in 1706, a more clear-cut achievement and the only time he did not have Eugene of Savoy at his side. More significantly, most of the time on the battlefield Marlborough was fighting mugs. The only time he came up against significant opposition - Marshal Villars at Malplaquet in 1709 - he barely scraped home on points after another murderous Pyrrhic victory that nearly destroyed his reputation.

Marlborough never faced significant opposition: there is no equivalent of Caesar vs Pompey, Bayazid vs Tamerlane, Turenne against Condé or Wellington vs Napoleon. Sadly, a judicious assessment has to place Marlborough well down in the ranks of great captains.

The man John Churchill, as opposed to the military hero Marlborough, was a human disaster: venal, avaricious, treacherous, without a single moral bone in his body. He and his dreadful wife Sarah fully deserved all the opprobrium heaped on them by Swift and Macaulay. It is heartening to see a millionaire with a playboy image writing a book of serious history, but Spencer's talents should be spent on someone more deserving.

Frank McLynn's new book is '1759: the year Britain became master of the world' (Cape)