Documentary about restoration work on the iconic clock tower, which will see the bells silenced for the next four years. Anna Keay, Director of Landmark Trust, goes behind the scenes on this massive project, and talks to Parliament's principal architect and the three clockmakers who have the challenging task of taking the gigantic mechanism apart for the first time in nearly 160 years. The programme also examines the history of the clock tower, revealing how it was almost never built in the first place.