Time Team first went to Canterbury for the 2000 Live, when excavations were carried out at three sites: Greyfriars, Britain's first Franciscan friary; Blue Boy Yard, within the precincts of the former Roman temple; and a medieval tile-making complex just outside the city at Tyler Hill. These excavations provided a tantalising insight to the wealth of archaeology, covering almost 2000 years of continuous occupation, lying beneath the surface of modern-day Canterbury.

In comparison with the excavations planned for the city's Big Dig, however, Time Team was merely scratching the surface in 2000. There has been no excavation to compare with it in Canterbury – nor indeed in the vast majority of British towns and cities, where archaeologists are normally restricted to 'keyhole archaeology', investigating small and scattered sites as and when they become accessible.

The area under development is known as Whitefriars, after the friary that once stood here. It comprises six separate sites that will be excavated over four years. Time Team followed the excavation at Phase One, an area about the size of a football pitch, located right on the high street.

All the most recent signs of human occupation of the site – basements and concrete foundations – were stripped away by machine. The site had been so badly cut through by modern development that the archaeology existed only as what Tony Robinson described as 'a series of islands in a sea of dereliction'. 'It's a mass of confusion that would strike fear into the hearts of most archaeologists,' said Tony. But not the team from the Canterbury Archaeological Trust, who are in charge of the Big Dig.

Over the nine months that Time Team followed the excavations, the CAT team painstakingly investigated layers of occupation that took them back to Roman times. (This part of the site, at any rate, appeared not to contain any earlier remains of any significance.) An unexpected number of post-medieval rubbish pits, which took more than a month to excavate, rather than the planned week (and even then CAT director, Paul Bennett, described it as 'heartbreaking to whack them out the way we are'), provided the first in a series of delays to the schedule. But eventually the team was able to get down to the medieval and earlier layers.

In doing so, they were able to piece together large volumes of information about not only the Whitefriars friary church, built here in 1324, but also the earlier development of Canterbury, including the laying down of the main street plan that can still be seen today. Time Team's own contribution to the process of discovery, meanwhile, included tracking down a document from Henry IV in 1408 giving permission for the friary to reconstruct buildings facing the high street. It seems that redevelopment schemes have long been a feature of Canterbury's townscape.