A GREEK farmer, who was a great lover of all things Mycenaean, led two archaeologists, Konstantinos Kourouniotis and Carl Blegen, to a hill site inland from the bay of Navarino, on the west coast of the Peloponnese, in 1938. He reckoned this was "sandy Pylos" at the heart of the fabled Homeric kingdom of King Nestor.

The following year, the first trial trench at Epano Englianos, which had to be cut in such a way as to avoid an olive grove that another farmer refused to allow to be cut down, found an archive deposit of Linear B tablets, which confirmed the site's importance.

The Second World War pre­­vented the excavation of the palatial site, and in 1945 Kourouniotis, who had been searching for ancient Pylos since 1920, died. The American Blegen recommenced digging in 1952 and later published the excava­tion, humorously dedicating the work to "the goddess who protects the olive tree".

In 1954, the Illustrated London News featured an article about the extraordinary finds, with a detailed reconstruction of the 105-room palace of the Neleids by Alan Sorrell, a former commercial artist and war-time RAF airman. An illustration of his still appears in the current guidebook to Pylos, a site which is also undergoing
recon­struction, and will be inaccessible until 2015.

The authorship of this meticulous drawing is immediately recognisable to anyone who grew up with the series of illustrated histories that Sorrell produced in the 1960s, or who benefited by the scholarly guide­­books that the Ministry for Public Buildings and Works used to pro­vide. Stonehenge, Verulamium, the great abbeys of Fountains, Melrose, and Dryburgh, all leapt to life with his characteristic bird's-eye view.

Unlike the Greeks, the British seem to have abandoned his evocat­ive and accurately detailed recon­structions. The latest guides to Old Sarum and Stonehenge which I bought this summer from English Heritage now look as if they have been illustrated by someone who de­­­­­­signs computer screens for action games.

But Sorrell (1904-74) was an insightful artist, and his draft designs often have marginal queries that he sent to the archaeologists and historians to check or recon­sider. When he drew Roman London, he included a seawall along the Thames, which the archaeolo­gists insisted was wrong. Only after his death was evidence of that wall found at Blackfriars.

Sorrell had shown early promise, and in 1928 won the Prix de Rome. Two years at the British School at Rome, in the heart of Fascist Italy, allowed him time to travel across the much troubled peninsula and brought him under the spell of Piero della Francesca, whose great frescoes at Arezzo he copied. In the library in Rome, he finally read Clive Bell's 1914 Art, and his reading of Cézanne increasingly informed his neo-Romantic abstract style.

Landscapes became littered with fragments of a lost past, and forms were reconfigured into half Roman­esque shapes. These translated well to the commercial demands of the pre-War Post Office and London Transport. A view of St Mary's, Hen­­­­­­don (for London Transport), in Coronation year, includes two fig­ures among the tombs, one of whom gestures heavenward. To a Chris­tian, it could be read as the Arch­angel bearing comfort to the young widow. In the light of the on­set of war, the leaden sky almost pre­­­­­figures the gathering storm-clouds.

But it is perhaps only his reportage work that showed any real inspiration. He had witnessed the six-day celebration of the marriage of Prince Umberto of Savoy and Princess Marie José of Belgium in January 1930, and his watercolour of a night-time carriage procession of King Emmanuel III surrounded by his own troops, the Corazieri, and Mussolini's Bersaglieri is atour de forceof Vorticism.

Sorrell was not always a fortunate man, and, like many holders of the Prix de Rome, he had a later career that was uneven. He was not appointed as a war artist, was sacked by the Royal College of Art after nearly 18 years' teaching, and failed to become head of Winchester Art School. He seems to have been a prickly man, and his work is presented with filial piety by a son of his second marriage.

Much of Sorrell's early work was lost, seemingly with his first mar­riage, although the little show in two rooms at Sir John Soane's Museum presents an interesting but limited artist.

He is perhaps at his best when at his most pictorial, as in the murals that became a signature of public art in the 1920s, and which reached an apogee at the 1951 Festival of Brit­ain.

In 1932, Southend Council com­missioned him for four busy nar­rative scenes, of which The Building of Prittlewell Church Tower was shown at the Royal Academy Summer Exhibition in 1936. Even before his training as an airman, working for camouflage units, his bird's-eye view is distinctive.

Sorrell had hoped to be able to produce a series of modern-life and contemporary scenes, but the Mayor had other thoughts in mind, and en­­couraged Sorrell to portray historic events in the life of the town.

Stanley Spencer would have made so much more of it; but in the flaxen-headed shepherd boy fol­lowing his flock with his cloak caught in the wind, and in the woman with her babe-in-arms standing next to the church fence, there are hints of a story that is commonly called Christian; discrete, effective, and yet pale.

Rather more successful to my mind, because it is much less crowded, are the panels that he painted for the Nelson bar on the disused aircraft carrier HMS Campania when it was transformed into a floating art gallery during the Festival of Britain in 1951, touring coastal ports and towns with the work of 60 contemporary artists.

These panels had passed to Harlow Arts Trust, but have been recently sold off by the council to Paul Liss, one of the organisers of this exhibition. Here there is no "dirty British coaster with a salt-caked smoke stack", but Sorrell has painted in the spirit of John Mase­field's 1917 "Cargoes". A Thames sailing barge, Orkney yole, Deal galley, Shetland nessy yole, Norfolk wherry, and Aberdeen fifie are among the boats that litter the scene like so many pub signs.

Outside his native Essex, Sorrell received one important church commission in the same year, which was in the diocese of Chichester, for the nave paintings at St Peter's, Old Bexhill, in East Sussex. The far-sighted Bishop George Bell had long sought to encourage his parish clergy to beautify and celebrate their churches and, while not all such commissions were successful, the arcade at Old Bexhill still looks fresh.

The patron saint of the diocese is scorned by the phlegmatic St Wilfrith/Wilfrid on one side of the arch, while on the west side the man from Tarsus startles St Peter from his fishing nets. The composition is deliciously naïve, and is set in an invented landscape with Tuscan angels flying banderols above the heads of the saints. The presentation drawing would have delighted any PCC or DAC, and one wonders whether Sorrell saw himself as Wilfrith, the outsider and troubling presence.

"Alan Sorrell: A Life Reconstructed" is at Sir John Soane's Museum, 13 Lincoln's Inn Fields, London WC2, until 25 January. Phone 020 7405 2107. www.soane.org