Countryfile - 08/02/2009

John Craven heads to the hallowed seat of learning which inspired Darwin's love of natural science, Cambridge University. Miriam O'Reilly takes a look at Britain's worst rat problem for the last thirty years, and investigates whether rat hairs and droppings could be getting into the food chain. And Juliet Morris searches for an ethical Valentine date, while Adam is back on the French roads as the British heavy horse team compete on the Route du Poisson.