Even the man from Oxford Archaeology knows. Ian Miller is the man in charge of the dig in Wigan town centre which has been enabled by the building of a new 425,000 sq ft shopping development. Townsfolk have always prided themselves that somewhere around Wigan was the site of the Roman settlement of Coccium.

"Twenty years ago we weren't even really sure if there was anything Roman of any consequence in Wigan," says the archaeologist. "But we have now found a stone building with underfloor central heating from the early second century, a time when most Roman buildings in the north were timber."

His hunch is that he has found a mansio - part of the Roman postal system which would have doubled as a guest house for visiting imperial dignitaries. "The town must therefore have had a strategic purpose. In terms of Roman Britain it has elevated Wigan from the 4th division to the premiership."