People living near the Brynglas Tunnels on the M4 in Newport are being urged not to worry if they hear sirens or see smoke or flashing lights in the area tonight.
The two tunnels to the east of Cardiff will be shut overnight for an emergency services exercise.
Traffic Wales South says the emergency services exercise will be between 8pm tonight (Tuesday) and 6am tomorrow.
“Smoke, sirens & flashing lights may be visible/heard in the area around the tunnel. Please do not be alarmed, this is part of the exercise,” it explains.
(Picture – Mapillary)
