The Museum of London Archaeology Service began as the Department of Urban Archaeology (DUA) in the early 1970s. It is associated with, but is now separate from, the Museum of London and undertakes many of the important excavations that have transformed our knowledge of the archaeology of London.

The DUA was set up in response to the destruction of the archaeology by the large scale development of the City of London. It was part of the Rescue archaeology movement. The danger of the loss of archaeology was pointed out by an important publication called The Future of London's Past by archaeologist Martin Biddle.

The DUA was led by Brian Hobley and revolutionised understanding of London's early history. These included:

Complete rewriting of London's archaeological history

Excavation revealed that the historical narrative about the Roman occupation of Londinium was very flawed. London did not begin in 43 AD immediately after the military construction of London Bridge nor did London continue to expand until the end of the Roman period. Instead the intensive archaeological work in the 1970s and early 1980s was able to show that London was not founded until about 50 AD and that it began a spectacular boom which reached its height in the early 2nd Century AD and that subsequently, it began a long and slow decline which left it virtually deserted by the end of the Roman period.

Discovery of Lundenwic

Excavation in the City of London had failed to find virtually any evidence of occupation in the period from 410 AD to the 10th Century despite unambigious historical evidence of London's existence at least from 604 AD onwards. However, the DUA's archaeological partner, the Department of Greater London Archaeology (DGLA), had discovered so-called Saxon farms in the area of Fleet Street, Covent Garden, and Westminster. In the mid 1980s Alan Vince and Martin Biddle independently came up with the idea that after the Dark Ages, London had restablished itself not in the City but a couple of miles west in the areas noted above, centred on the area called Aldwych and which was known as Lundenwic. In 886 AD Alfred the Great moved the Londoners back into the City of London which was known as Lundenburgh.