The BBC history department has traditionally worked on the principle of primogeniture - male will succeed male - but more recently the corporation has been making a determined effort to replace male presenters with female ones.

The latest is Dr Helen Castor, whose new programme is Joan Of Arc: God's Warrior (Tuesday, BBC Two, 9pm). But is she any good?

Sadly, there are one or two problems. First, is she obnoxious enough? David Starkey has opinions that shouldn't be let out in public and Niall Ferguson is good on telly because he doesn't really care if you disagree with him; he has the swagger of a boy brought up in Glasgow combined with the arrogance of a man educated at Oxford. But Dr Castor looks and acts a little like a Labour leadership candidate trying to offend no one and appeal to everyone. Perfectly nice, but too nice to get anyone very excited.

Dr Castor also falls short on another crucial test. The best television historians are a little crumpled, disorganised and ungroomed. Simon Schama has that disobedient hair of his and gesticulating arms that make him look like he could have been made by the Jim Henson Workshop, and Max Hastings in his disorganised suits has the manner of a bufter telling a story in his club. Dr Castor on the other hand is too neat and careful and a little bit too M&S. In this slick age, history presenters should be a little bit charity shop. It's the last bit of eccentricity we have.

As for her programme on Joan of Arc, it was well made on a tight budget, although it could have done much more to explore the fact that Joan is a historical figure but a modern figure too. Five hundred years ago, Joan talked of voices from God at a time when almost everyone believed in gods and demons, but our increasing secularism does not mean that she is increasingly irrelevant. Quite the opposite: her faith, and its consequences, mean that she is immediately and utterly relevant to our modern experience and some of the political and security challenges we face.

The relevance lies in what Joan was: young, committed and willing to fight. Those qualities have made her an icon for all sorts of people on the left and the right, Catholic and Protestant, men and women, but they also mean she is just as frightening as she is admirable. Joan believed that she was fighting a war for God and it meant she could be reckless, uncontrollable and utterly unreasonable. In her, there was the same combination of faith and youth that drives men and women into the arms of ISIS.

Then as now, facts could not shake the faith. When Joan, at the head of the Dauphin's army, freed Orleans in just four days, it was proof that God really had spoken to her and approved of her mission. Later, when her military adventures went wrong and she was captured by the English, Joan did not think for a minute that her divine experiences were undermined - her defeat was simply proof that God had no further use of her. There was never any question that God was involved, watching and intervening.

From an agnostic or atheist perspective, it is hard to admire this part of Joan's character because it led her to make stupid decisions such as trying to capture Paris with an inadequate force. What is easier to admire (although it too was driven by her faith) is the way in which she was able to crash through some of the barriers of 15th-century society. Joan was a peasant, a woman, uneducated, illiterate and yet there she was, at the centre and the top of French society. Faith may have inspired that transformation, but her personality made it possible, which is why Joan of Arc's status as an icon of history is deserved and secure.