Former Formula 1 driver Jarno Trulli has slammed the way that the sport has changed since he stopped racing seven seasons ago.

The Italian, now 44, contested over 250 grands prix, but now laments the state of F1 today.

"What has Formula 1 become?" he told the blog of Italian journalist Leo Turrini.

"Do you realise that in Singapore the drivers were 10-12 seconds per lap slower than the pole time? It's absurd, ridiculous.

"I imagine the dismay that guys like Kimi [Raikkonen], Fernando [Alonso], Lewis [Hamilton] and Seb (Sebastian Vettel) must feel, as they knew the Formula 1 that really was Formula 1.

"That F1 pushed from the start to the finish, but now you need to look after consumption, the tyres, so on. Without intervening quickly, this distortion of formula one risks becoming irreversible.

"I regret it enormously because I love this world - it represented so much of my life. What a pity."

However, Trulli said that he has been genuinely impressed with Hamilton this season.

"He has always been strong but usually something goes wrong with him, but this time he has made no mistake. I'm sorry to say it but he has been better than Vettel," he said.

"For Ferrari, the dream is fading once again."

Hamilton leads Vettel by 40 points going into this weekend's Russian Grand Prix.