At low tide on the foreshore of the Thames near Vauxhall Bridge in central London, a series of timber stumps is visible. How old are they, and what was their purpose? Time Team have the task of finding out, before the stumps are destroyed forever. They want to create a picture of the Bronze Age landscape here, 3,500 years ago. Post holes would indicate dry land building, while piles (pointed stakes driven into the ground) would indicate a structure above the river. To find out, they have to dig up one of the massive stumps. It's a race against time and tide to get it done in three days. Phil helps Damian Goodburn to make a simple piledriving rig with authentic tools. Stewart and Mick take a trip on the London Eye, to help them map the course of the ancient river. They are joined by Gustav Milne from University College London, and Jon Cotton from the Museum of London.

• Tim Taylor

• Tony Robinson
• Bill Oddie
• Phil Harding