There was a bit of sad news for the Time Team crew this week, but the show must go on. Tonight they're heading to Lincoln Castle, where a £19million refurbishment project is well underway. There's been a bit of an archaeological dig going on ahead of the restoration, and it's thrown up a few secrets about the former jail. Phil Harding and Alex Langlands team up with Tony Robinson to reveal the tale of the Victorians, who appear to have launched a rather gruesome experiment in prison justice...