With only 19 legible tablets previously known from London, the find from the first decades of Roman rule in Britain provides a wealth of new information about the city's earliest Romans.

While wood rarely survives when buried in the ground, the tablets were preserved by the absence of oxygen in the wet mud of the Walbrook, which dominated the area in Roman times but is now one of London's many buried rivers.

Recesses in the rectangular tablets would originally be filled with blackened beeswax, which would have been written in using a stylus, and while the wax has not survived the writing sometimes went on to the wood and can be deciphered.

Sophie Jackson, archaeologist and director at independent charitable company Museum of London Archaeology (MOLA), which led the dig, said: "We always had high high hopes for the Bloomberg dig, situated in the heart of the Roman and modern city and with perfect wet conditions for the survival of archaeology, but the findings far exceeded all expectations.