Niki Lauda is against a Mercedes engine supply deal with McLaren, and would "veto" any arrangement with the struggling British team.
Despite comments from its management which insist that McLaren's power unit future will remain with Honda, rumors continue to ramp up about the partnership's impending demise.
Mercedes AMG F1 boss Toto Wolff denies however the solution will be as simple as a reunion of the old McLaren-Mercedes name.
"It's important for Formula 1 that Honda remains," he said.
"I have no doubt that they will solve their problems."
And Mercedes team chairman Lauda's resistance to a McLaren-Mercedes revival is even clearer.
"I would veto it. Two years ago, I pleaded for us to give Red Bull our engines.But I wouldn't do it today.
"We have to concentrate fully on our duel with Ferrari rather than upgrading another of our rivals," the F1 legend told Auto Motor und Sport.
A McLaren-Mercedes deal also seems to have been ruled out by the sporting regulations, which require engine changes for the following season to be registered with the FIA by 15 May.
“Want to win a trackday experience? All you have to do is subscribe to our FREE newsletter HERE”
GALLERY: All the action from Barcelona on Sunday
Keep up to date with all the F1 news via Facebook and Twitter
