The first Steam Christmas Family Lecture with BBC TV personality and historian Adam Hart-Davis is sold out.

Called What the Victorians Did For Us and due to be delivered early on Saturday evening, the lecture has drawn interest from across the South West, and will be held inside the main exhibition hall, in the shadow of the GWR locomotive, Caerphilly Castle.

Mr Hart-Davis will talk about the engineering and cultural legacy left by Victorian inventors and engineers such as GWR creator Isambard Kingdom Brunel.