At the Canadian Grand Prix, Raikkonen made a mistake in the closing moments of qualifying when pole was up for grabs. He then finished sixth, one place lower than he had qualified, while teammate Vettel won the race from pole position.

The Finn is out of contract at the end of the current campaign and Brundle, one of the lead presenters for Sky Sports, believes Ferrari has a very obvious decision to make if it wants to compete for the constructors' championship in the near future.

"Ferrari have to be concerned about Kimi," Brundle wrote in his weekly blog. "l know he's one of the most popular drivers around, but after another mistake in qualifying he finished nearly 30 seconds behind his team-mate on Sunday.

"What are they going to do? In my view Kimi has reached the end of the road. He still shows a flash of real speed from time to time but he can't relentlessly deliver the required race pace any more.

"Nor is he working as an effective rear-gunner to Seb. Winning the Constructors' Championship is super-important to Ferrari - they don't put the list of their titles on their road car dashboards for fun - and if they want to win it in this era against Red Bull or Mercedes they need a [Daniel] Ricciardo or a [Charles] Leclerc alongside Vettel next year. And Vettel needs to deal with that."

Brundle reserved special praise for Sauber rookie Charles Leclerc, the Ferrari junior and reigning Formula Two champion. Leclerc has continued to impress and already has 10 points to his name this year, having scored top ten finishes in Azerbaijan, Spain and Canada.

"Charles Leclerc looks the real deal to me. He is out-performing his Sauber car just like Alonso and Webber did in a Minardi, like Senna did in a Toleman and Schumacher in a Jordan. He stands out a mile and really impressed me a month ago in Spain when he didn't wilt with Fernando Alonso on his tail.

"He clearly has the head for F1, and he just looks like the complete package, even if his picture in the F1 grid graphics make him look like a startled Harry Potter. Ferrari don't often take risks on young drivers but there's a changing of the guard going on between generations - the field can be divided into three groups with the likes of Fernando and Kimi at one end, Grosjean and Hulkenberg in the middle ground, and a group of young fliers coming through -- and Ferrari don't want to be caught out."