Hartley and Perez disagree over Bahrain mix-up

Perez, qualified a place behind Hartley, overtook the Kiwi at the start of the formation lap - and the Toro Rosso driver only reclaimed position when both cars had already returned to the grid.

This was in violation of the rules, and a post-race investigation yielded 30-second penalties for both drivers, as well as two penalty points on Hartley's licence.

Perez said: "Formation lap off the line I overtook him, but then he didn't retake back his position as he didn't realise that I overtook him.

"He thought I was always going to start in front of him, so he didn't retake back his position.

"I'm quite surprised about why I got the penalty. I've been overtaken many times, I've overtaken many times, but always the guy behind retakes his position.

"But Hartley didn't do it, and we both got a penalty.

"I have to speak with Charlie [Whiting, race director] on this one. I was quite surprised.

"You can see on my video that I'd really slowed down a couple of times to make him pass, but I thought he had a problem.

"What I don't get is why I got the penalty."

Hartley admitted that Perez's overtake caught him off-guard, but he insisted the Mexican did not make any special effort to let him back through.

"He overtook me with such conviction, it was a bit surprising - and then I had other things to focus on," Hartley said.

"To be honest, on a formation lap, we have quite a few jobs we have to do, in terms of temperatures, in terms of synching the gears, switches, we have a lot of processes and procedures.

"Perez wasn't acting like, trying to let me pass, and that's the truth of it, and I was honest with the stewards as well.

"I think Perez also didn't realise he was out of position - if he told you another thing or not, I don't know.

"I don't know why he passed me, he almost overtook [Carlos] Sainz or [Nico] Hulkenberg before Turn 1 as well."

The original stewards' ruling from Bahrain sided with Hartley's interpretation, saying Perez "made no noticeable effort to allow [Hartley] to regain his position".

The penalties had no impact on the Bahrain GP's points finishers, with Perez and Hartley - who also collided in the race - demoted from 12th and 13th to 16th and 17th respectively.

Hartley, a recent convert to grand prix racing from the World Endurance Championship, added that F1's limits on formation lap team radio communication were something he is "not used to" and contributed to the mix-up.

"In the past, it would be like, radio - 'OK you need to take back the position' - but we're actually completely blind on the formation lap, so that's pretty much the story.

"Anyway, it's a mistake both of us probably won't make again."