Mercedes bosses Toto Wolff and Niki Lauda have labelled the clash between team-mates Lewis Hamilton and Nico Rosberg as “unacceptable” after the title race took another twist at the Belgian Grand Prix.

Rosberg clipped the left rear tyre of Hamilton while challenging for the lead on lap two at Les Combes, which resulted in a puncture for the Brit sending him to the rear of the field.

As a result, Hamilton was unable to recover from the collision and retired from the race, while Rosberg went on to finish second behind race winner Red Bull’s Daniel Ricciardo.

The incident is the first time the team-mates have collided and has been met by a strong stance from both Wolff and Lauda, with the latter issuing an apology to Hamilton after the race.

A team meeting involving both Hamilton and Rosberg was due to be held at the Mercedes motorhome to discuss the clash.

“It was an unacceptable risk,” Wolff told Sky Sports F1.

“This is an absolutely unacceptable race for us. In lap two our drivers crashing into each other…unbelievable.

“There is one rule and that is that you don’t crash into each other. And it has happened not at the end of the race but on lap two. If there is any rev limiter [for anger] I’m in there. It’s important there are rules and they’re followed.”

Hamilton, who witnessed his rival open up a 29 point lead in the title race, was baffled by the incident before defending his reason to retire from the grand prix.

“I didn’t really understand what happened – I felt a big thud at the rear,” said Hamilton.

“I gave the guy space. I don’t really understand it.

“It’s really gutting for the result and for all my team.

“We’ve had such a tough year, not just the guys on my side of the garage, but the whole team in general.

“This is not good for the team. We could’ve easily had a one-two.”

“I could do nothing. I was driving the arse off the car and the thing was all over the place.

“I couldn’t catch Romain Grosjean. It didn’t even matter if the Safety Car came out, I wouldn’t have been able to pass. [Adrian] Sutil was pulling away from me.

Rosberg was informed of Wolff and Lauda’s critical reactions to the collision with the German claiming he would respect their opinions.

“I haven’t heard it myself from the people you mention but I will respect their opinion, said Rosberg.

“All I know I was faster and I gave it a go, the inside was locked so I gave it a go around the outside.”

The championship leader, who was booed on the podium by the crowd, also believes the situation will not destroy his relationship with his clearly aggrieved team-mate.

“I am confident that we can keep it,” added Rosberg.

“It is always going to be an intense battle, that was clear from the outset and there will always be difficult moments.

“But after Hungary we had a discussion again, we will discuss this again today, review it and then move on.”