Kimi Raikkonen's return to Sauber in 2019 is one of the most extraordinary stories of a busy and unpredictable Formula 1 silly season.

Most observers took the view that if and when Charles Leclerc was confirmed at Ferrari, the ousted Raikkonen - who turns 39 next month - would slip away into retirement. Why would he want to take a few steps down the grid when he's spent most of his career in cars that at least had a shot of winning races?

But he has never been one to conform to expectations, and instead he has taken on the challenge of helping to reboot the team where he started his F1 career back in 2001.