Prof Ged Martin follows King Richard II as he rides along the A12 Colchester Road to murder his uncle

Imagine you're a Havering peasant in 1397. It's harvest time and you're working in the fields near Gallows Corner.

Suddenly you hear trumpets and clip-clopping horses - oh no, it's the King and his entourage! Richard II was visiting his palace at Havering-atte-Bower. These people have swords and horsewhips. Hide behind the hedge until they've gone!

Richard had become a boy king in 1377. England was ruled by his powerful uncles. It took him years to dislodge them.

Richard's grandfather, Edward III, and his own father, the Black Prince, had won glorious battles against the French, at Crécy in 1346 and Poitiers ten years later.

But Richard II, a cultured man, preferred peace. Wars were expensive. The Poll Tax of 1381 had triggered the Peasants' Revolt, which began at Brentwood.

In 1396, as a diplomatic move, Richard "married" the French king's daughter. Unfortunately, Princess Isabella was only seven. It would be years before there might be a grown-up Prince of Wales. Hence Richard's relatives remained important - and they thought him a wimp.

Uncle Thomas of Woodstock, Duke of Gloucester, was the classic opposition politician. From his castle at Pleshey, near Chelmsford, he told everybody he could beat the French and cut taxes - an impossible combination. (In fact, his only campaign in France, in 1380, failed because his soldiers caught dysentery.)

In 1397, Richard decided that Thomas was one uncle too many.

Some accounts say he borrowed part-time soldiers from the Lord Mayor of London, Richard Whittington - Dick of the pantomime - and arrested his uncle at Pleshey for treason.

Another version stresses trickery. From Havering Palace, the king visited Pleshey without warning.

We don't know his route, but he probably crossed the woodlands of northern Havering before following the line of today's Straight Road to join the A12 Colchester Road.

Richard reached Pleshey at dinner time, insisting that his surprised uncle must accompany him to London at once. His counsel was needed at an important meeting the next day.

Unsuspecting, Uncle Thomas mounted his horse and came along, escorted by just eight attendants.

On the return journey, Richard avoided the main road, fearing that unsettling rumours of his coup would spread from towns like Brentwood.

Instead, they headed across country and through Epping Forest, uncle and nephew chatting in the saddle as they trotted along.

Somewhere near Stratford, the king suddenly spurred his horse and cantered on ahead. Hidden in roadside trees was an ambush led by Thomas Mowbray, Duke of Norfolk. He owned the Romford manor of Mawneys: Mowbrays Road in Collier Row remembers him.

Uncle Thomas was grabbed and hustled away to Calais, then an English foothold across the Channel. Calais was like modern Guantanamo Bay: normal rules did not apply. Soon news came that the king's uncle had mysteriously died. He was buried in Westminster Abbey.

The Duke of Gloucester's murder simply stirred more aristocratic opposition. In 1398, Richard was forced to exile his cousin Henry Bolingbroke. A year later, Bolingbroke returned, proclaiming himself King Henry IV. Richard was deposed, and murdered soon afterwards.

Pleshey is a 25-mile drive from Romford. The Duke's stronghold has long since disappeared, but the 50-foot-high castle mound and the watery moat remain.

The pleasant village has a long main street - called The Street. Nearby, the semi-circular Back Lane marks the castle's inner defences. Opposite the church, a half-mile footpath follows the outer earthworks around the village.

The castle site is private, but there's a viewpoint and picnic spot halfway along The Street. You might catch a glimpse of one of England's oldest brick bridges, sloping up to the castle site, possibly constructed by Duke Thomas himself.

I do hope Havering's peasants hid behind the Harold Wood hedges and in the Harold Hill woods when their king rode by that summer day. Richard II was in a mean mood.

There's a specialist term for murdering your uncle, avunculicide. I'm sure you'll never need it.