Jenson Button and Lewis Hamilton call for overtaking rule clarity

Jenson Button and Lewis Hamilton have joined a chorus of drivers calling for clarity on overtaking rules.

Drivers are confused about what is acceptable defensive behaviour after two incidents involving Mercedes' Nico Rosberg at the last race in Bahrain.

Hamilton, who was involved in one of the incidents, said: "Fortunately neither of us got in trouble or hurt.

"Hopefully we will try to make the rules a little bit clearer so we won't be in that position again."

The drivers will discuss the issue, which has dominated the build-up to this weekend's Spanish Grand Prix, at their briefing with race director Charlie Whiting on Friday.

Button said he felt one of either his McLaren team-mate Hamilton or Rosberg should have been penalised for the incident, in which the German drove right to the inside edge of the track to defend from Hamilton, who then passed him after going beyond the boundaries of the circuit.

"The problem with that manoeuvre is if Nico doesn't get penalised for pushing off the track, that means Lewis overtook off track," Button said.

"One of them should have been penalised whereas they both got away with it. It's difficult to know where the line is then."

Button's view was backed by Red Bull's Mark Webber, who said: "I was surprised Lewis was allowed to keep his position.

"It was for sure a situation Lewis didn't want to put himself in either, finding himself completely off the track, but ultimately the move was allowed to be kept.

"I'm sure we'll talk a bit more about it in the drivers' briefing."

Rosberg was also involved in an almost identical incident with Ferrari's Fernando Alonso, who has since said that he feels the situation opens the door to drivers pushing their rivals off the track and to overtaking by going beyond the boundaries of the circuit.

The F1 rules forbid drivers from passing off the track - but they are less clear in defining acceptable defence.

There is a rule saying drivers have to leave room for their rivals - but only in the context of a move back onto the racing line after leaving it to defend.

There is no rule saying a driver in front cannot choose which part of the track to use to defend his position - only one saying he cannot crowd a rival off the track.

Rosberg was not penalised because race stewards in Bahrain said footage showed he moved first in both incidents and neither Hamilton nor Alonso had any part of their car alongside him before he made his initial defensive move.

Rosberg said: "I judged it to be harsh but fair, according to the rules we have and I didn't judge that it was putting my compadres in danger."

He added that it was "important" the issue was discussed at the drivers' briefing "because two drivers raised their concerns about it, two of the drivers who were involved.

"So we need to discuss it because they felt in danger which I didn't intentionally do, of course not," he added.

He said the rules regarding such a situation were "not very clear", adding: "It's difficult to make rules for that but it can be looked at, so there are specific guidelines as to when you need to leave space."

Alonso said this week he felt there was a lack of respect between some of the drivers, but Rosberg and Button both said this was not the case.

Asked if he had respect for his rivals, Rosberg said: "Of course. For all of them."

Both Button and Webber's team-mate Sebastian Vettel said Rosberg would probably have behaved differently on a track that had grass or a wall demarcating the edge of the circuit, rather than the asphalt in Bahrain.