With-flow bus lane ahead

This sign means: With-flow bus lane ahead which pedal cycles and taxis may also use. It is an information sign. Information signs are all rectangular and tell you about the road and what is on it.

Official Highway Code caption: “With-flow bus lane ahead which pedal cycles and taxis may also use.”

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