The Lighthouse, by P D James<br/>End in Tears, by Ruth Rendell

Heroes for all seasons

Hero is the name "given to men of superhuman strength"; to a man "admired for his achievements and noble qualities" who "exhibits extraordinary bravery, firmness, or greatness of soul". Not every novel has to have a hero, but a crime novel must. Where the hero is also a policeman, his heroic qualifications can only be those his current generation accept. The later half of the 20th century, and the present day, favours nobility with flaws. We no longer wish to venerate without having something to criticise. The virtues of the crime-solving hero must reflect the era. He need not be fashionable, but he cannot be laughable and lasting. Which is why the achievements of P D James and Ruth Rendell are so extraordinary.

The virtues of James's Commander Dalgliesh and Rendell's Chief Inspector Wexford were selected more than 30 years ago; they have lived through changing times without any licence to change themselves. Like all heroes, particularly investigators, they have to infuriate. They have to be insistent followers of red herrings; they have to be foolish as well as wise, and have sufficient weaknesses to make them credible while remaining consistent.

How to make a character emerge again and again in a crucial role without boring the reader to death is an enormous challenge, which many authors in the genre fail. So how do these two Queens of Crime keep their awkward heroes fresh?

Judging from their new novels, there is one, crucial secret. Both authors like their central men, and remain vividly interested in them, which is infectious all by itself. They continue to write about them as if they had only just met them in a new reunion on the page.

Another secret to the characters' longevity is that, however mistaken they have been, neither loses dignity, although they risk it all the time. They stay alive in the imagination as someone we would like to meet again because they are intrinsically curious and honourable - qualities which are ultimately more interesting than villainy. They are the voice of our conscience, because they are always aspiring to justice, even when doubting it. Self-doubt and self-deprecation are very English lasting virtues.

Yet Commander Dalgliesh and Chief Inspector Wexford might not like each other. There would be mutual respect, for sure, but possibly not a great deal of curiosity. They have led very different lives. Adam Dalgliesh is the son of a Norfolk parson, a poet and unlikely policeman. He was already a Commander in 1977, his fictional career having skipped low-level crime to allow him to emerge as a fully-formed figure of authority, handpicked for the sensitive homicide case where discretion was vital. He was relatively free from restraint and allowed to employ the iron fist in the diplomatic, velvet glove.

Equally clever, Wexford might envy him his easy passage, and also the fact that he has aged a mere ten years or so in the three decades since his creation. What keeps Dalgliesh from being insufferably privileged is his self-awareness. Murder, says James, is the result of strong emotions, and Dalgliesh knows that the discovery of the culprit will create as much suffering as the murder itself.

The investigation is conducted more in sorrow than in anger, with a ruthless objectivity which he often regrets. Dalgliesh is a poet first, with the writer's ice chip in the heart which will always keep him aloof. In every book, somewhere, he articulates his inability to engage with life, as when he sees a man worry about his children and realises that there was a whole territory of experience on which, once repulsed, he had turned his back - and that this rejection somehow diminished him.

He's innately kind, but immune to sentiment, the first to touch the body and the first to retreat into the self. Part of Dalgliesh's enduring appeal is the fact that you always want to disinhibit him, long for him to throw caution to the wind, to dance the light fantastic and at least blow someone a kiss. In The Lighthouse, he does, although ever so quietly, and there is much rejoicing.

If Wexford heard the news, he might say, "You took your time, didn't you?" For Wexford, a yeoman to Dalgliesh's patrician, has always been fully committed to ordinary life, living among women naturally. Wexford is always known by his surname, or "Guv", which he hates. He has his wife Dora, and a difficult daughter, and he has grown with them all and his small town, which he knows is a true microcosm of the world.

In End in Tears, he is not only old and tetchy, but progresses into greater tolerance. Wexford stays fresh because he is the opposite of Dalgliesh, always fully engaged as the shrewd, participating commentator on the present, always up to date and often appalled by new insanities. Wexford knows that fresh initiatives in the war against crime only produce greater ingenuity in the invention. He regrets; he accepts.

Where Dalgliesh is singular, Wexford is a singular everyman. You choose which one you want to hug, but their lasting appeal merely proves that good men are hard to find. Hang on to them if you can.

Frances Fyfield's new crime novel is 'Safer than Houses' (Little, Brown)