Kohli scored 103 to add to his first innings 97 and declared on 352-7 to set England a mammoth 521 at Trent Bridge.

"There are many really great players but he is the stand-out across all the three formats of this era by a country mile," Vaughan told Test Match Special.

"He's got the gift to play all around the wicket in every single format."

Kohli's second century of the series, coming after he was dropped by Keaton Jennings on 93, took him to 440 runs in six innings, more than twice as many as the second leading scorer in the series.

The 29-year-old's prolific form is in stark contrast to his first tour of England four years ago, when he made only 134 runs in 10 innings with a top score of 39.

"On this tour he has left well and made the bowlers bowl to him," Vaughan added. "It looks to me as though he has been working on this for some time and come with a clear plan.

"He is a wonder player. There were questions about if he could bat in English conditions. No question in my mind; he is the best batsman in the world across all three formats. He is an unbelievable player."

Kohli's 23rd Test century moved him level with Steve Smith, who is top of the Test batting rankings. England assistant coach Paul Farbrace, though, thinks that the India captain should be rated above the Australian.

"You would be hard pressed to argue against him being seen as the best player in the world at the moment," Farbrace said.

"The way that he has developed, he has played fantastically in this series. I like the way that he plays the game. It's fantastic to see someone playing the game in that way.

"He's a high-quality player and he's shown that he's learned a lot on this tour alone. He deserves the runs that he's scored.

"Our bowlers might argue that he's been given too many chances, but he's shown he is high quality.

"I'm a big believer in players learning from players. Our players should be watching the way he has played."