Japanese GP: Lotus must 'control' Romain Grosjean says Red Bull boss

Grosjean hit the back of Mark Webber at Turn 2 on lap one of the Japanese Grand Prix - and was latter slammed as a "first-lap nutcase" by the Australian.

Webber subsequently stormed down to the Lotus office unit in the Suzuka paddock to confront Grosjean and vent his anger at what he felt was a totally avoidable incident.

Further adding to the criticism of Grosjean, who was banned for the Italian GP for having caused a first lap crash in Belgium, Horner declared it was up to Lotus to intervene and sort its driver out.

"Hopefully he will have a good look in the mirror after this incident - or his team need to get him more under control," explained Horner. "He [Grosjean] is capable of doing it, as he is obviously a quick driver, but so many incidents is unacceptable at this level.

"He needs to really talk to himself, or the team needs to talk to him, because not only is it dangerous for others, but he has cost himself and his team a colossal amount of points - together with the innocent victims that he has collected en route."

Horner said that the biggest concern for Red Bull, and the reason why Webber was so angry, was that Grosjean had not appeared to have learned any lessons from his Monza ban.

"I think Mark has every right to express his feelings, and I think that it was just a complete misjudgement [by Grosjean]," he said.

"The most important thing when you make a mistake is to learn from it, and I think the most disappointing thing is that it is a repeat incident and proved extremely costly for Mark, as it did for [Lewis] Hamilton and [Fernando] Alonso at Spa, and numerous other victims earlier in the year.

"I think the most worrying thing is he doesn't appear to be learning from his mistakes."