One of the items discussed in this week’s F1 Strategy Group was a change to the car regulations to retain a big engine fin – which could be used to display the larger car numbers the FIA wants to see.

But despite extensive work having been put in to create rules, and teams already starting work on their 2018 concepts, McLaren did not vote in favour of the suggestion – as the Woking-based outfit instead wants a smaller version introduced.

With unanimous support needed for a change, McLaren’s failure to back it means that the proposal will not go through, and moves are now being made for a compromise solution to be found.

The decision means that teams now face potential difficulties in finalising some of their aero characteristics ahead of the rear wing. This could have a big impact on those outfits that have already put a lot of development work into the original larger fin idea.

McLaren is pushing for the smaller fin because it believes that the current rear wings of cars are not visible enough.

Racing director Eric Boullier also suggested that his outfit may prefer a smaller fin because it better suits their car concept for 2018.

“Maybe we have found a way to use the engine cover that works better,” he said. “The cars are complicated today so it is difficult for Zak [Brown, CEO] to find big stickers.

“But we are not playing games. Everyone is developing their own car so if you ask for something which is against our interests, I will not go for it.

“Some teams have tried to play something that was more suiting their car model, or whatever. But we have a regulation in place for next year, so if there is no unanimity then there is no reason to change.”

Force India COO Otmar Szafnauer expressed some frustrations that his team faces uncertainty about its 2018 car design at such a late stage – as he questioned McLaren’s motivation.

“We have to release an engine cover soon, it would be nice to know the rules,” he said. “I thought we had it all agreed.

“McLaren, I believe, wanted to expose the rear wing more, but the rear wing isn’t exposed only because it sits so low now. That is why you cannot see the sponsor. More so than because of the fin.

“The fin hides it from certain angles but not from head on – you can’t see the fin from head on. You cannot see the rear wing because it is so low. For us it removes a pretty big area for the sponsors.”