Honda's CEO said it was "difficult" to explain why Nissan would make a good business partner. Analysts believe that Honda's ideal partner for a merger would be a more "healthy and financially sound company.

Speed limits are usually intended to prevent drivers from going too fast. Occasionally, though, they warn against bumbling along the road too slowly. Honda Motor boss Toshihiro Mibe and his Nissan Motor counterpart Makoto Uchida will need reminding of this if they don’t soon shift out of low gear for the tie-up they proposed on Monday.

Japanese automakers Honda and Nissan will attempt to merge and create the world’s third-largest automaker by sales as the industry undergoes dramatic changes in its transition away from fossil fuels.