Trotman spent his whole career of 50 years in the London Museum, later the Museum of London, with the exception of service in the Royal Air Force in the Second World War. He had been selected for the museum in 1936 as a "boy learner" by Mortimer Wheeler, then Keeper of the London Museum. Three years later he packed the collections for dispersal to safe storage in tube tunnels and a Rothschild mansion in Buckinghamshire. Returning after the war he found that the museum's home in Lancaster House, overlooking Green Park, had been appropriated by the Foreign Office and he moved the collections again to Kensington Palace for the new Director, W.F. Grimes, the second of seven for whom he worked.
Grimes required him to do one last job at Lancaster House, where the Roman Boat remains found at County Hall in 1911 had been damaged by War Reserve Police. He recreated the boat - mainly it has to be said in plaster - but it could not be moved until some years later.
The diversity of his skills can be seen in hundreds of objects now displayed in the Museum of London. One especially stands out, the Roman silver pot and strainer from the Temple of Mithras, discovered in 1954, which emerged corroded and was thought at first by Norman Cook at the Guildhall Museum to be a 19th-century inkwell.
As materials science made great advances in conservation Trotman was able to include more of the results in the work of his laboratory. Equally importantly he was able to ensure that proper standards for temperature, humidity and light were applied to the new stores and galleries of the Museum of London.
Not surprisingly, his knowledge of the London collections and their needs was vast. The new Museum of London in the Barbican, opened in 1976, for the first time provided reasonable display and storage conditions and well laid-out laboratories which he designed. There Trotman encouraged and trained a growing staff of conservators, and as Head of Conservation saw his discipline finally play its proper role alongside curators and educators in the work of a modern museum. A regular flow of students from the Institute of Archaeology, at London University, came to the lab and learnt the value of practical experience and were entertained with stories of the old London Museum and its sometimes quirky personalities. He also acted as an examiner for Museums Association qualifications in conservation.
In many ways his heart remained at Kensington Palace, and in a smaller museum where he could practice all his skills including joinery, delicate metalwork, picture restoration and exhibition design. The opportunity to take an exhibition of "The British Royal Family Collection" to Japan in 1967 gave him a chance to use all of them in an unfamiliar environment - and to describe the exhibits to the Emperor and his family over tea.
Trotman became a Fellow of the International Institute of Conservation in 1977 and a Fellow of the Society of Antiquaries in 1981.
Arthur Trotman, conservator: born 4 July 1921; conservator, London Museum, Museum of London 1936-86; married 1942 Elizabeth Chambers (one daughter); died London 5 October 1995.