While Toto Wolff admits that he regrets being unable to sign Max Verstappen he is unsure whether partnering the youngster with Lewis Hamilton would have worked.

The Austrian has revealed that he held talks with Jos Verstappen and his manager, Huub Rothengatter, in 2013 as Max was preparing to make the switch from karts to single-seaters.

At 15, Max had won the European and World KF and KZ championships - an unprecedented feat in the history of the discipline - made all the more significant by the fact that he was the youngest ever driver to win the KZ world championship.

Having made his single-seater debut at Pembrey in October 2013, he subsequently tested for several Formula Renault 2.0 teams before making his racing debut in the non-championship Florida Winter Series in early 2014.

Already eyeing F1, Jos Verstappen approached Wolff, however at that time Mercedes did not have a junior team and it was later that year that Max was snapped up by Helmut Marko's Red Bull junior programme.

A year later Max signed to Toro Rosso, making the move up to Red Bull at Barcelona in 2016.

The rest, as they say, is history.

"I spoke to Jos and Huub when they came to my office in Brackley," Wolff tells ESPN, "that must have been when Max was in karting or the end of his karting days, just before Formula 3.

"We spoke again when Max and Jos visited me in my house in Vienna," he continues. "We spent a few hours discussing his future.

"Do I regret missing out on Max? Certainly," he admits. "But it wasn't an option back in the day. We had two drivers that I was extremely happy with, in Nico and Lewis, and when Nico left, Valtteri was then the option and Max wasn't even available."

However, the Austrian admits that he is unsure if a Hamilton-Verstappen teaming would have worked.

"Would Max and Lewis have functioned? Maybe not," he says. "Lewis is a Mercedes guy since forever, so that hard question I never needed to ask myself for the organisation. Everything happens for a reason.

"But I had two drivers in the seats, no deal with a junior team, so it was clear that the option with Toro Rosso was what they needed to do. And they did well."

Interestingly, based on his early F3 results, Wolff admits uncertainty as to just how good Max was.

"Back in the day I think there wasn't huge hype around Max, because Max and Van Amersfoort weren't winning the championship that year. Esteban (Ocon) won in a more competitive car.

"So the insiders knew that Max probably was in an inferior package and in his first year, and the insiders knew there was a very good one coming, but it wasn't clear that he was that good at that stage.

"You can only say when someone grows in Formula One and matures that he is a true world champion, an outstanding one. Before we had Lewis and then Michael Schumacher and before that Senna.

"Who is the next one? Was it clear that Max would step into these shoes? It wasn't clear back then."

Asked if there were any subsequent approaches to the Dutch driver, Wolff replies: "We always had friendly contact but never discussing driving."