Toto Wolff has stressed Lewis Hamilton and Nico Rosberg are on a 'final warning' following their controversial coming together on the final lap of the Austrian Grand Prix, but refused to detail what a second 'yellow card' offence would entail.

Ahead of the British Grand Prix, Mercedes revealed it would not impose team orders on its two title-challenging drivers after threatening the measure in the wake of a third incident in five races. On that occasion, Hamilton claimed victory, while Rosberg - who was blamed and punished by stewards for the clash - slipped back to fourth.

Nevertheless, Mercedes expressed it has amended its 'Rules of Engagement', which it expects its drivers to respect, without going in to specific detail as to what this entails or explicitly say what another offence would lead to.

It was a line Mercedes F1 boss Wolff was keen to maintain when faced with media at Silverstone, remarking that discussing specific terms would 'belittle' the drivers.

"It is a very difficult task because they are wired in a certain way," he said. "They drive a Mercedes because it is exactly how they are but we have had an accumulation of accidents in the last couple of races that has led to a situation that we somehow we need to contain. This is the tricky bit because if you have a yellow card, will it change your way of thinking or not? Because you know what happens with a second yellow card and it is a scenario that none of us wants to be in.

"The fundamental principle is the moment the lights go green, they have a responsibility, we are not sitting with them in the car, it is just two of them. We provide them with the best possible car but once the race is on only the two of them are able to manage the situation, which is a good thing because it is entirely within their hands and the outcome is in their hands."

However, when asked whether banning one of the drivers was on the table, Wolff did not ultimately rule it out, adding any further sanction would be a negative impact on their title hopes.

"If I would answer the question it would go into detail," he said. "You know how a driver is calibrated and what is important for a driver so it is clear that if it would happen - which is entirely in their hands - it is something that would have a negative outcome for their campaign.

"The drivers are heroes. The stars of the show. I don't want to belittle them in public and by answering the question there is a risk I would do so, so I will not go there."

Rosberg was handed a ten-second penalty for the accident, with Hamilton's win allowing him to reduce the margin to the top of the standings to 11 points.