Putting pressure on the on the FIA to finalise the 2017 test programme, Pirelli motorsport director Paul Hembery has threatened to quit the sport as they will not have time to prepare new tyres for next season.
Pirelli have given F1 bosses till the end of Monday to make a decision after weeks of back and forth between the FIA, team bosses and the tyre company.
Hembery explained that over the years teams have complained about the driveability of the tyres and added that if they want to see significant changes next year then they will have to act immediately.
"When I land [after the deadline on Monday afternoon], if I don't have an email confirming it's approved, or something else positive, then you will be calling me for a different story," the 50-year-old revealed to Motosport.com.
"This is it. We cannot do our job without this. We cannot deliver. We are being asked to make very significant changes, by changing the driveability of the tyres.
"Plus the thermal challenge that we have been given from the outset is now changing, so we now have to give tyres that will have less degradation and less wear.
"And they have to be tyres that the drivers will have a wider window of opportunity to push on. So it is a big change, and big performance improvements – so time is running out. We are in mid-April."
Enjoy the full experience of the 2016 FIA Formula One season on FOX Sports Play, where you can catch LIVE races from angles unseen before, exclusive interviews, behind the scenes, in-depth analysis and so much more. Don’t miss it!