Honda motorsport boss Yasuhisa Arai admits supplying a second team would not necessarily help improve the power unit manufacturer's performance.
Having returned to F1 in partnership with McLaren last year, Honda had the opportunity to supply a second team in 2016 when Red Bull requested engines as it looked set to split with Renault. McLaren boss Ron Dennis blocked such a move, with Red Bull eventually reverting to run Tag-Heuer branded Renault engines.
With Honda again only supplying one team this season, Arai told Autosport there would have been limited benefit to having two teams using its power unit.
Asked if supplying another team would have helped Honda, Arai replied: "I don't think so because the 'size zero' concept is unique to McLaren-Honda so whether that power unit will work with a customer team, we don't know.
"One thing I can be sure of is that if we had a second team the progress in reliability would increase but I don't know about performance."
Arai has previously confirmed to F1i that Honda and McLaren will continue with the 'size zero' philosophy in 2016.
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