By PAUL JOHNSON

Given the option of picking an unsullied hero from all English history, I'd go for Henry V, the victor of Agincourt on St Crispin's Day in October 1415.

He was probably the most able man ever to sit on the throne and has a strong claim as the greatest of all our monarchs.

Henry of Monmouth, as he began life (Monmouth was where he was born), was tall, wellbuilt, athletic, with brown eyes and hair kept closely clipped around the back and sides (like any well-turned-out soldier), clean shaven and with a powerful speaking voice.

He was extremely decisive and could be fearsome. Yet he was well liked, respected and trusted by all those, high and low, who had dealings with him.

A medieval king of England did an executive job. He was head of state and head of government, head of the armed forces, leader ex officio of the nobility and the landed interest, the active patron of the merchant class and ultimate source of justice for the peasants.

He took all important decisions, or delegated them at his peril, and was always on the move to be at the scene of the action. Medieval kingship wore a man out. Henry was inducted into this life of toil, risk and exposure the hard way.

Once, when I was giving a history lesson to the late Princess Diana, we discussed the predicament of a person born to be king. She said she had found her husband - who had been heir apparent from birth - to be utterly selfish and self-centred because he had been spoiled from the cradle on.

I pointed out that this was the common fate of heirs apparent and that they rarely matured into successful monarchs, unless special circumstances made their childhood or youth exceptionally hazardous.

Henry V fits into this analysis. His father, the rich and powerful Henry Bolingbroke, was viewed with suspicion by the King, Richard II, who exiled him, confiscated all his property and took the 11-year-old boy as a hostage for his father's good behaviour.

Had Richard been a more decisive and ruthless man, young Henry's life might well have been forfeit when his father invaded England to seek redress and then to claim the crown for himself as Henry IV.

Instead, aged 12, the boy was declared "Prince of Wales, Duke of Aquitaine, Lancaster and Cornwall, Earl of Chester and heir apparent to the kingdom of England."

These were not empty titles. The revolt of Owen Glendower in Wales, trouble in Scotland and the tendency of discontented English nobles to seek the return of Richard to the throne meant that the King had to unload some responsibility on his young heir's shoulders.

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