In a secondary school on the outskirts of Tallinn, the capital of Estonia, a pupil scrawls the solutions to mathematical equations on a whiteboard. His teacher, a young woman, stands at the back helping to guide the student and encouraging his peers to comment. In a chemistry lesson down the corridor, two students race to scribble out formulae for compounds while their classmates offer helpful critiques.

Such cleverness is easy to find in Estonian classrooms: its teenagers rate as the brainiest in Europe. In maths the country’s 15-year-olds post test scores that suggest they are roughly a year ahead of British children, and two years ahead of American ones.