No buses

The no buses sign, a red circle around a black bus, means no bus with more than 8 passenger seats may go past it. It is a sign giving orders: signs with red circles are mostly prohibitive. Cars and other vehicles may carry on unless another sign says otherwise.

Official Highway Code caption: “No buses (over 8 passenger seats).”

Listed under “Signs giving orders” in The Highway Code: traffic signs (GOV.UK). For every sign in more detail, see the Department for Transport’s Know your traffic signs.