During a lengthy drivers’ briefing on Friday evening, new FIA race director Niels Wittich, who is alternating the role with Eduardo Freitas this season, made it clear that drivers can no longer use non-fire retardant underwear under their suits while in their cars. 

The FIA is concerned some drivers have been wearing underwear that is in breach of the safety regulations. 

According to Appendix L of the FIA’s International Sporting Code, drivers are instructed to wear gloves, long underwear, a balaclava, socks and shoes that are homologated to the FIA’s standards. 

Red Bull team principal Christian Horner revealed the discussions had led to an “entertaining” drivers’ briefing on Friday. 

“I certainly won't be checking our drivers' underwear!” Horner said. 

"For compliance, I see that as a team manager role, although I'm reliably informed our drivers go commando! Hopefully, it won't be an issue for them. 

“I've yet to meet the race director. Obviously, they're doing the best job they can with the rules they have. I understand it was an entertaining drivers' briefing yesterday. 

“In the interests of weight-saving, whether you're losing jewellery or underwear at the moment is quite helpful for us.” 

Asked whether the FIA was being too rigorous after several reprimands were handed out during Friday practice for impeding incidents, Horner replied: “I think it's something the drivers actually requested but there needs to be an element of common sense. 

“Too many penalties in a practice one...the biggest thing as a deterrent for the drivers is a fine. That tends to be what hurts them the most so maybe we should look at fines rather than reprimands and potential grid penalties. 

“You don't want to be over-zealous in P1 on a circuit that is relatively new. It's something that's discussed at great length in the various meetings. We just need to come up with something to simplify some of these regulations.” 

Hamilton and Verstappen joke about jewellery ban 

The move comes after the FIA reminded drivers about a ban on wearing jewellery during on-track sessions, which led to an entertaining exchange between Lewis Hamilton in Friday’s pre-event press conferences. 

The full wording of the rule, which forms Article 5 of the third chapter of Appendix L from the governing body’s International Sporting Code, states: “The wearing of jewellery in the form of body piercing or metal neck chains is prohibited during the competition and may therefore be checked before the start.”

Asked about the FIA’s reminder, Hamilton, who is regularly seen wearing jewellery in the F1 paddock, joked: “Well I’ve got certain piercings that I really just can’t take out, that not many people know of… Nah I’m kidding! 

“It’s been the rule forever, since I’ve been here it’s been the rule, so nothing new. I’m just going to come with more jewellery next week.” 

Asked the same question, Verstappen replied deadpan: “I would be too heavy if I wore jewellery, so it’s not possible.”

A smiling Hamilton then responded: “I know you have a nipple piercing man, come on…” before Verstappen laughed and said “you want to see it again?!