For the past 220 years, Ordnance Survey have been mapping Great Britain with extraordinary accuracy. But as Gareth discovers when he visits their HQ in Southampton, GB's master map is not a static printed document. It's a 2 petabyte database which is updated up to 20,000 times a day. This adds up to 360 million updates a year. Since the development of the theodolite and the first detailed map in 1801 of the county of Kent, Ordnance Survey have used cutting edge technology, not only to map our lands, but to manipulate, understand and ask questions of the geography of our natural landscapes and built environment.

Voices on the train, public address announcements at the station, automated telephone banking, Alexa and Siri. We are surrounded by electronic voices. But very little research has been done of how we respond to synthetic speech. To investigate the impact of artificially generated voices in our lives, BBC R&D together with our favourite acoustic engineer, Professor Trevor Cox of the University of Salford, has just launched a study. The Synthetic Voices and Personality Test, is an online test we want you to take part in. Please go to https://voicestudy.api.bbc.co.uk and have a listen

Presenter Gareth Mitchell