One cannot possibly make this up. Only in a thoroughly statist, freedom-denying country could this be true, and that is what Britain is today.
Remember: "It's for the children." The Left always finds a way to use child welfare as a way to micro-control even the most personal aspects of people's lives. Next they will surely ban romance, falling in love and getting married, because after all, all marriages end in either death or divorce, and those things are so upsetting - maybe even more upsetting than best-friend fall-outs.
Link, where you may go on to read: "Instead, the primary pupils are being encouraged to play in large groups."
Ah yes, the Left's love of collectivism, for making people cohere to large groups, whose entry and exit are naturally defined by the Left, is a topping means to keep control of the proles, is it not? (Which is one reason the Left has a fetish about mass transit.)
Don't forget that Britain is a land where the government levies a tax on the view out your living room window.
