Two-time champion Fernando Alonso on Wednesday said some of Formula One's most classic circuits had been "assassinated" in the modern era of hybrid cars and called for change.
The Aston Martin driver's remarks came after his home Spanish Grand Prix at the Madring circuit was criticised for a lack of overtaking opportunities and described by reigning world champion Lando Norris as "not a great race track".
Alonso said his disappointment with the experience of racing in F1 this year extended to many other circuits and cited the British Grand Prix at Silverstone, the Belgian race at Spa-Francorchamps and the Japanese event at Suzuka as among those diminished.
He said he hoped the sport would find a way of recovering the thrill of racing in F1 for the drivers, with more changes to the balance between engine and battery power likely.
"Maybe from the cockpit, behind the wheel, especially if you drive other categories or have experienced other F1 cars, there's a bit of frustration," Alonso said.
"Silverstone, which is an incredible track, is no longer fun," he said.
"At Spa, it was almost embarrassing going through Eau Rouge and, at Suzuka, the 130R," he said, referencing once-daunting corners.
"There are circuits that have been assassinated this year."
Alonso is 19th in the world championship standings with just three points. Kimi Antonelli leads the way on 292.