Carlos Sainz Jr will start the Monaco Grand Prix from the pitlane after failing to stop at the weighbridge during Formula 1 qualifying.
Sainz qualified eighth in his Toro Rosso, but he now faces an arduous race from the back after being penalised by the FIA stewards for his indiscretion.
A statement read: "The driver failed to stop for weighing during Q1 when signalled to do so by the red traffic light.
"The car was not returned to the FIA garage and work was undertaken.
"In accordance with article 26.1 (iv) of the FIA Formula One Sporting Regulations the driver is required to start from the pit lane."
Sainz, speaking ahead of being called to the stewards along with a team representative, said: "The red light on the entry to the pit lane is in a place where I cannot see it.
"I saw it late, but then the next time I stopped at the weighbridge and it was fine.
"They should change the position of the light, to be honest, because I didn't see it."
Autosport has produced a standalone special magazine to celebrate our 70th birthday. All current print subscribers will receive a copy for free. To order your copy of the 196-page Autosport 70th Anniversary issue, please go to: autosport.com/autosport70th