Britain's history is rich in fiery queens, and the first such heroine, tall with red hair down to her waist, commanding and brave, was Boadicea, warrior leader of the ancient Britons.

She lived at the same time as the emperors Claudius and Nero, and led a surprisingly successful British revolt against Roman rule in AD60-61 (which, for reference, was when St Paul was writing epistles and St Mark composing his Gospel).

She was a notable orator. Her enemies, the Romans, said her voice was strident, but, as Margaret Thatcher found, any woman seeking to establish authority over an assembly of men is open to this accusation.

The history we have of her from such a distant epoch is part fact, part fiction, and not much is really known with certainty about her. But her name lives on and her tragedy rings a kind of muffled bell in all of us.

The Roman historian Tacitus - who wrote within living memory of the rebellion and was therefore nearest to the action in literary terms - records that she was the wife of Prasutagus, king of the Iceni, a tribe in what we now call East Anglia.

He had made a deal with the Roman conquerors that when he died his co-heirs would be his own two daughters and the Emperor Nero. That way he hoped to preserve his kingdom and his family fortune.

But, on his death, the Romans ignored the will, flogged Boadicea, raped her daughters and seized all her husband's property and estates. As a result, says Tacitus, the Iceni rose in revolt, backed by the Trinobantes, a tribe from what is now Essex.

This army of Britons destroyed the Roman colony at Colchester, annihilated the ninth Roman legion, which came to relieve the town, and forced the Roman Governor of Britain, Paulinus, to evacuate London, which was also destroyed. Seventy thousand Romans were killed.

The rampaging Britons targeted places where "loot was richest and protection weakest," wrote Tacitus. "They could not wait to cut throats, hang, burn and crucify, as though avenging, in advance, the retribution that was on its way."

It duly arrived. Paulinus collected 10,000 troops and lured the Britons into a pitched battle on grounds of his choosing, at a place Tacitus does not identify but seems to have been somewhere in the Midlands.

The Britons congregated in huge numbers, on foot and horseback, and "their confidence was so great that they brought their wives with them to see the victory, installing them in carts stationed at the edges of the battlefield."

Boadicea (or Boudica as she is more often called these days) is said to have driven round all the tribes in a chariot with her daughters in front of her, and addressed them in a fighting speech with marked feminist over-tones.

She showed them her bruised body and outraged daughters, and ended with the rallying cry: "Win this battle or perish. That is what I, a woman, plan to do. Let the men live in slavery if they will."

Tacitus says that more than half the British army were women, and the outcome was an easy Roman victory. Eighty thousand Britons fell at a cost of 400 Roman dead and a slightly larger number of wounded.

The queen, he adds, poisoned herself, and the rebellion ended not only in defeat but terrible famine among the surviving Britons.

But that may not be the whole story. A century and a half after Tacitus, a Roman senator named Cassius Dio wrote a history of Rome in 80 volumes, with a more detailed version of the conquest of Britain and Boadicea's uprising.

He put the number of Romans slain at 80,000 and said the whole island was lost for a while in this "terrible disaster". What added to Rome's shame, he wrote, was that "all this ruin was brought about by a woman".

His explanation for the uprising was economic mismanagement on the part of the Roman masters. They had unreasonably called in large loans of money made years earlier to prominent British chiefs.

This rings true. The Roman occupation of Britain was marked by brutal financial exploitation of the ruling elites and oppression of the natives of all degrees.

Dio says that Buduica (or Budhika), as he calls her, was chosen leader by the tribes and "directed the conduct of the entire war". He says she had "greater intelligence than is generally found in women," was "very tall, in appearance most terrifying, in the glance of her eye most fierce, and her voice was harsh.

"A great mass of the tawniest hair fell to her hips. Around her neck was a large golden necklace. She wore a tunic of many colours over which a thick mantle was fastened by a brooch. She grasped a spear to help her terrify all who saw her."

She practised magic and divination, and concealed a hare in her garments, which she would let escape to see how it would run so as to make her prophesies.

Her followers are portrayed as savages, and Dio describes obscene cruelties inflicted by them on Roman women, for example, cutting off their breasts and sewing them onto their mouths.

The speech he ascribes to her spurring on her followers was along the same lines as Tacitus's: freedom or death - better to perish in battle than live under Roman rule as slaves.

But it contains an added note, with great historical resonance. The queen stressed that the Britons were a special people, separated from the rest of mankind by a sea, and enjoying, until the Romans came, a liberty unknown elsewhere.

According to Dio, her army totalled 230,000 and the final battle, far from being a rout, was very close. Many Britons escaped and were preparing further resistance but the queen fell sick and died.

The Britons "mourned her deeply and gave her a costly burial. But feeling that now at last they were really defeated, they scattered to their homes".

The archaeological evidence to support all this is both firm and disappointing. Firm because a black and red layer of ash discovered in the earth confirms that Colchester and London were burned down in about AD60. But disappointing because of the warrior queen herself and her army no physical evidence has yet been found.

A large area surrounded by deep ditches at Thetford in Norfolk has been called "the palace of Boudica", but similar sites exist elsewhere and their purpose is debatable.

Yet she is an immensely striking and even attractive figure - and national concept - and, in the absence of real evidence, imaginations have worked hard.

In the early 16th century, a history of Britain presented her as "Voadicia", a Northumbrian lady and had her burning down Doncaster. A chronicle of Scotland made her a Scottish heroine from Falkirk.

Then, around 1614, the playwright John Fletcher wrote a play called Bonduca, which cunningly surrounded her with druids, King Caractacus and other bits of ancient British furniture - though to please his own king, James I, Fletcher made her a witch and a horrible woman.

Rallying the troops: Boadicea inspired Britons to fight for their freedom

Fifteen years later, a historian named Edmund Bolton produced the theory that Stonehenge, whose purpose and date had baffled antiquarians, was in fact Boadicea's tomb.

Over the centuries, other sites for her burial place were canvassed - such as Parliament Hill Fields in London and Gop Hill in Flintshire, where locals said they had seen her ghost driving a chariot.

There is another theory, held by people who congregate for the summer solstice at Glastonbury, that she is buried deep below Platform 8 at King's Cross Station.

Interest in her increased in the late 19th century alongside the belief that Britain's unwritten constitution was of immemorial antiquity and that she had played some part in its foundation.

Gladstone encouraged the sculptor Thomas Thornycroft in the massive presentation of the queen in her chariot, with her two daughters, that stands at the northern end of Westminster Bridge, opposite Big Ben.

Queen Victoria, who thought her predecessor's treatment by the Romans "outrageous" (she too had been widowed early and had many daughters) was particularly keen that Boadicea should be given a fine memorial.

It is certainly a splendid piece of work. Children love it, and so do feminists. It inspired the suffragettes in their campaign for votes for women, and it crowns Queen Boadicea as a heroine for ever.

Though not entirely undisputed. A British author named Gildas, writing in the sixth century, was part of a British ruling class who benefited from the Roman occupation, and he had a different take on the warrior queen.

To him, far from being a hero, Boadicea was "a treacherous lioness" who butchered the governors the Romans left to rule the country.

We should not be surprised by this portrayal of her as a "baddie". Throughout history, one person's hero has been another's villain. That is particularly so with modern heroes.

In America, men like the outstanding steelmaker Andrew Carnegie and the oilman John D. Rockefeller became heroes of the cult of the entrepreneur. But to others they were "robber barons" or, in the words of President Theodore Roosevelt, "malefactors of great wealth".

People must agree to differ about heroes. I admire Chile and its people greatly, but I was concerned when my friend Salvador Allende became its president and opened the country to hordes of armed radicals from all over the world. The result was the world's highest inflation, universal violence and the threat of civil war.

So I applauded the takeover by General Pinochet and still more his success in making the economy the soundest in Latin America. But by preventing the transformation of Chile into a communist satellite, the general earned the furious hatred of the Soviet Union, whose propaganda machine successfully demonised him among the chattering classes all over the world.

It was the last triumph of the KGB before it vanished into history's dustbin. But Pinochet remains a hero to me.

My other heroes tend to be people who successfully accomplish things I would not dare even to contemplate. I could not possibly sail single-handedly round the world, even if I had the skill, like a pretty and fragile woman of my acquaintance, Clare Francis.

The man who runs a fruit stall near my house has swum the English Channel several times for charity. He is a hero for me. I admire heroines of the Far Eastern slums like Mother Teresa, who was a realist as well as an idealist (as are most true saints). The vicious attacks sometimes launched on her fill me with horrified fury.

I always have a soft spot for those who speak out against the conventional wisdom and who are not afraid to speak the truth even if it puts them in a minority of one. And in this case there is some common feeling, for during most of my life I have been outspoken and have suffered accordingly.

I think we appreciate heroism most if we have a tiny spark of it ourselves, which might be fanned into a flame if the wind of opportunity arose.

So how do we recognise the heroes and heroines of today? First, by absolute independence of mind, which springs from the ability to think everything through for yourself, and to treat whatever is the current consensus on any issue with scepticism.

Second, having made up your mind independently, to act - resolutely and consistently. Third, to ignore or reject everything the media throw at you, provided you remain convinced you are doing right. Finally, to act with personal courage at all times, regardless of the consequences to yourself.

All history teaches, and certainly all my personal experience confirms, that there is no substitute for courage. It is the noblest and best of all qualities, and the ne indispensable element in heroism in all its different manifestations.