F1 Commission members have until later this afternoon to back proposed changes to the testing rules to allow Pirelli to conduct 25 car days of development for 2017's new wider rubber.

The move has come after a frantic few weeks of dialogue between Pirelli, the FIA and teams over sorting out the testing plans, amid Pirelli concerns that it was close to the point where there was not enough time for it to get next year's wider tyres ready.

Motorsport.com has learned that Pirelli wrote to the FIA earlier this month to make it clear that if the 2017 test programme was not sorted immediately, then it would have no choice but to withdraw its tender application for the 2017-2019 F1 contract.

That move, and the acknowledgement of how serious the situation had become, prompted F1 race director Charlie Whiting to recently visit senior representatives from the company in Milan for a meeting to push the testing agreement forward.

Following a subsequent meeting with teams in China last weekend, agreement was reached for a plan for five teams to join in a programme that would run from July over a period of 25 car days.

Final approval needed

The change to the rules to allow testing has now gone to the F1 Commission for approval, with a deadline of today to be sorted.

And if it does not get the necessary support, then Pirelli motorsport director Paul Hembery has made it clear that his company will be forced to walk away.

“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,” he told 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.”

Michelin lessons

Hembery confirmed that senior management at Pirelli had got agitated at the failure to finalise testing plans earlier – and the problems that Michelin have faced in MotoGP this year on its return only added to the urgency of getting things sorted.

“You see other categories where people have come into a sport and had big problems and we are in this sport,” he said.

“There are big changes happening. We are being asked to make big changes, the drivers are asking for change – and yet we are being left without the tools to do it. People can argue we don't need to test, but we do.

“The solution we have is a good one, but the time taken to get there has been too long.”

End of the line

Hembery has long insisted that a 2017 plan had to be finalised by the end of April, but is clear that matters will be now be defined by approval regarding the testing rule changes today.

When asked specifically what will happen if someone blocks the plan on Monday, he said: “As I said...you will be calling me for a different story. Someone else can have that challenge then. There are plenty of other things to do in life.”