Geomag (767) Mechanics Motion 2 Magnetic Gears – 96 pcs, £27.95 from Amazon

Build moving models driven by the invisible forces of magnetic attraction and repulsion. Create a non-contact motion transmission system using the magnetic forces of attraction and repulsion. Learn the basics of magnetism and use them to create controlled magnetic reactions. Stimulates creativity, imagination, and intellect. Suitable for ages 7+

This is a brilliant toy. It is fantastic for learning and children play with it for hours. It is beautifully engineered and so clever. I cannot recommend it enough. My kids love it.