Popular polymath and Maggie's noted hero

In a 1987 television interview, prime minister Margaret Thatcher chose Michael Faraday as her historical hero. Touched by multiple greatness - as a scientist, a populariser and a public figure - he rose to fame having had only a rudimentary education. In her trademark style as a hectoring interviewee, Thatcher affirmed the questionable Victorian perspective that "the Good Lord's no respecter of backgrounds, never has been, he plants genius the world over and it's up to us to find it".

Whatever her motivations, she deserves credit for the role she surely played in securing Faraday's place on the English £20 note. Its artwork highlighted most of the great themes of his work - as the experimental physicist who discovered how to generate electricity from magnetism, the chemist who was the first to discover benzene and liquefy chlorine, the scientist who introduced a host of useful new terms into the language (including "anode" and "cathode") and the virtuoso lecturer whose performances lit up London's Royal Institution for three decades. What the banknote did not allude to is the aspect of his character that the art historian James Hamilton explores in his engaging new biography with hitherto unmatched thoroughness - Faraday's links with the arts.

Hamilton argues that it is helpful to think of the young Faraday as arriving at a crossroads, with one sign pointing to "art", the other to "science" (the signs are, apparently, orthogonal). In the final analysis, Hamilton believes that Faraday "was an artist whose mode of expression happened to take him towards the interpretation rather than the representation of the natural world".

Hamilton takes every opportunity to illustrate his intriguing thesis. He suggests that the 30-year-old Faraday was able to beat others to the invention of the electric motor in 1821 partly because the artist in him enabled him to visualise a way in which an unseen force may be translated into a physical action. Elsewhere, we hear about (and see examples of) Faraday's rather good drawings and laboratory diagrams - so good that he qualifies, in Hamilton's opinion, as an amateur artist. We learn that the Royal Institution was at the forefront of improving image production in the 1820s and 1830s, with the result that engravers and painters (including John Constable) frequently attended the institution and gave lectures there. One of the appeals of the invention of photography was that it touched Faraday's sense of vanity (rather priggishly disdained by Hamilton), leading him to be one of the most photographed figures in public life, illustrating his wish for his image to be preserved in the medium in which "science and art hold hands".

Hamilton establishes Faraday's interest in visual art, but he overstates his case. Creative imagination is a quality possessed by all top-flight experimenters (and, indeed, theoreticians) and I am not persuaded that his visual skills and his spatial awareness played a bigger part in his success than they do in the success of many other leading scientists.

Perhaps to underline his claim that Faraday was something of an artist manque, Hamilton is at pains to draw attention to Faraday's literary skills. There is no doubt that Faraday's plain yet vivid way of speaking translated into his scientific writing, which is clear and free of pomposity. But his writings on religion and the scenery on one of his Alpine holidays are toe-curling. If he was a great writer, his greatness was confined to his laboratory notebooks.

The work Faraday did in his laboratory at the Royal Institution is competently outlined by Hamilton, albeit in rather less detail than one needs to appreciate its significance. The book is much better at giving us a sense of the great variety of Faraday's work - in addition to his science and his lecturing, we hear much about his public work, first on naval and military matters (in the 1820s and 1830s), later as a committee member. Add to this his many contributions to public debate, in particular with peddlers of the paranormal and the feisty Charles Babbage, and one has the picture of a true workaholic. No wonder he spent quite a bit of his time recovering from exhaustion, notably by going on 45-mile country walks.

Hamilton is rather disappointing in his account of the contributions Faraday made to theoretical physics towards the end of his career. Although Faraday was no mathematician, he was one of the founders of field theory. His brilliant intuitive thinking provided the underpinning for the great Scottish theoretician James Clerk Maxwell shortly afterwards to set out his theory of electromagnetism. Later, Einstein used the field concept in his 1915 theory of gravitation. Einstein often spoke of his debt to Faraday and Maxwell, and even had pictures of them displayed prominently in his Princeton home.

Hamilton shows little sign that he appreciates the huge significance of this aspect of his subject's work. Worrying, too, are some of the passages in which Hamilton compares Faraday's talent and achievement to those of his contemporaries. Is John Ruskin's place in the nation's artistic expertise really comparable to Faraday's place in science?

It is only in the book's majestic final paragraph that Hamilton does full justice to Faraday's pre-eminence. Here, Hamilton remarks how teaching at his own university (Birmingham) has been strongly influenced by Faraday's example at the Royal Institution. Everyone who enters the university's Aston Webb building has to pass through a door with a statue of Faraday above it, along with the figures of Darwin, Watt, Beethoven and Virgil. This is the company in which Faraday belongs.

It would have been quite a feat for Hamilton to have lived up to his stated aim of producing the biography of the multifaceted Faraday. Although Hamilton has not quite succeeded in his ambition, he can be proud of having given us what is the most readable account of Faraday's life. For science historians, this biography is, despite its scientific weaknesses, indispensable. And Baroness Thatcher will love it.

Graham Farmelo is director, Dana Centre Project, Science Museum.