There is scarcely a more iconic image of Oxford than the Bridge of Sighs linking two parts of Hertford College above New College Lane. Millions of photographs of it must feature in albums across the world. At the weekend I was admiring a study of the bridge produced even before it was built. How so? Because it was the work of its architect. Who was he? For every reader who can name him I feel sure there will be a hundred others who cannot. Sir Thomas Graham Jackson, Baronet and Royal Academician, is not nearly as well known as he deserves to be in a city on which he left a mighty mark.

As his grandson Sir Nicholas Jackson (above) explained last Saturday night during a fascinating talk in Oxford: “He designed more buildings here than any other architect, including the medieval ones.” One which, to my shame, I had never previously visited was the chapel at Hertford where Sir Nicholas – organist, composer and honorary fellow of the college – was speaking. His address was arranged as part of the building’s centenary celebrations. His talk was followed by a reception at the Divinity School in the Bodleian Library, where many objects associated with the architect, including a number of his drawings and plans, were on display.

It was, alas, for one night only. Chatting with Sir Nicholas, whom I met five years ago at the opening of an exhibition of his grandfather’s paintings at Christ Church Picture Gallery, we agreed that the show ought to be more widely seen, if for no other reason than to heighten Jackson’s profile.

His name, curiously, is rather better known in Croatia than it is in Britain, chiefly as a consequence of his design for the campanile of Zadar Cathedral. Sir Nicholas finds himself in some demand as a speaker in the country, engagements which he is able profitably to combine with concerts of his music.

Already a fellow of Wadham College when he embarked on his architectural career, TGJ carried out some of his earliest design work there. His friendship with the Warden, the Rev John Griffiths, a man of great influence, led to his being invited to compete in a competition to design a tower, contemplated by Cardinal Wolsey but never built, over the great staircase at Christ Church.

“I boldly soared aloft with a lofty tower such I felt sure Wolsey had prepared for with a massive substructure,” he wrote in his Recollections. He lost the commission (and it went nowhere else), he believed, because “the Dean did not like his cathedral spire to be challenged”.

Shortly after, Jackson made another bold bid to transform the Oxford skyline with his proposal for a crowned spire as part of his important work at Brasenose College. As the distinguished architectural writer J. Mordaunt Crook writes in his recent history of the college (Oxford University Press), he came up with “a multi-buttressed pinnacle – gravity-defying, diaphanous – soaring high above the squarest of square towers; the tower itself pierced at its base with a vaulted ceremonial porch . . . It was ingenious; it was bold.”

It was also extremely expensive. So, though his design was one of the big talking points of the 1887 Royal Academy Exhibition, in the end he came up with a cheaper scheme for this important site on the High.

Mordaunt Crook believes Jackson to have been the perfect man for the job. “[His] style was distinctive: an eclectic compound of Elizabethan and Jacobean, flexible, secular and picturesque. The Anglo-Jackson style – a phrase borrowed by John Betjeman from Maurice Bowra – was exactly right for Brasenose. In the 16th century, its buildings had been Gothic Survival; in the 17th century a mixture of Gothic Revival and Renaissance. Now they were to be all three simultaneously: Survival, Revival and Renaissance. No wonder contemporary critics talked of ‘progressive eclecticism’.”

A series of college extensions followed in Oxford, at Corpus Christi, Lincoln, Somerville, Wadham, Trinity and Hertford (where his ‘eclectic’ borrowings included, besides the Bridge of Sighs, a staircase in the lodge copied from the Chateau de Blois).

Other notable public buildings included the Examination Schools (its deep windows modelled on those of Kirby Hall, Northants), the Boys’ High School in George Street, the Girls’ High School in Banbury Road, and the Radcliffe Science Library in South Parks Road. A busy man . . .