It's the force that drives prices down and wages up; that lets us take longer holidays and have better quality products. Outside of economics, it's the force that drove our ancestors out of the sea and turned us into human beings. Yep: it's competition time. This week Madsen explains why we can afford things we want without anybody having to intervene to force suppliers to sell things cheaply.

If you want to catch up with the series, the whole set of videos is here.