Eric Boullier says Honda ultimately 'took a step backwards' when it was given the opportunity to revive its F1 engine programme with the scrapping of the controversial token system.

Introduced in an effort to maintain some control of costs by limiting development of the V6 Hybrid power units, the regulation subsequently had the effect of preventing Honda from making the major changes it needed to bring its flawed engine up to standard.

With the 'token' system scrapped ahead of the 2017 season, Honda was expected to make a significant step forward with its 2017 engine but has struggled to extract performance and reliability from what is almost an entirely new power unit design.

Indeed, McLaren racing director Boullier says Honda went the wrong way with development because the scrapping of the token system prompted saw it abandon what it had already learned.

"The tokens weren't locking you into if you want a strategy for your engine. Luckily now if there are no tokens, tomorrow if you want to redesign 100 per cent of the engine, you can, which with the token system you couldn't. But still, we can see the design of our engine, the layout of our engine is different this year. We took a step backwards.

Despite this, Boullier says there is more potential in the latest engine than its predecessor and insists Honda is working hard to rectify its issues but has to 'take time' due to the sheer complexity of the formula.

"We know we can unlock more potential with this layout, but there is a price to pay if you go that path, so you have to be careful," he continued.

"It just seems how complicated these engines are to build up on the level of performance I think it's raising questions on how to do it and how to get there faster, obviously they're trying many things, they're working very hard there are a lot of resources involved but it's you just have to find the key to unlock the potential of this engine and the lack of winter testing

"I think they need to change the way they work on dynos they need to try to breakthrough I think the slope of performance but I think it's going to come."

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