"Mercedes hard to stop" says Coulthard

David Coulthard believes Mercedes advantage over its rivals is so great it is likely to carry over into 2016.

The former Grand Prix driver and McLaren Mercedes stalwart considers the German manufacturer's engine/chassis package as the very best out there although it's hard to tell by how much.

"Mercedes have a great package - the best engine and a car at least as good as the best of the rest," Coulthard said to the BBC.

"Together that has meant they have a significant advantage over the field and what we can't know looking from the outside is how much more they have in hand, particularly in terms of engine usage."

"How close do they run to the limit of their engine at any point? How much of a margin do they have whereby if someone edged a little closer, they have space to push the engine a bit harder? "

"We assume they push to the limit in qualifying and then run within a reliability margin in the races. "

In Russia, Mercedes clinched the constructor's championship with four races to go, but with the driver's title all but decided it's unlikely the Silver Arrows will be easing off anytime soon.

"It's very difficult to assess the realistic prospects of anyone catching them up in the near future," the Scot concluded. "Unless Mercedes make some kind of monumental mistake with next year's car. Which is not very likely."

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