Former world champion Sebastian Vettel has slammed Formula One’s decision to tighten radio rules, saying that drivers and teams should be free to say whatever they want to each other during a race.

“All the radio issues we’ve had, I think it’s a joke,” the Ferrari driver told reporters at the Hungarian Grand Prix.

The governing International Automobile Federation’s (FIA) Formula One race director Charlie Whiting issued a “technical directive” to teams on Wednesday to clarify what they are allowed to tell their drivers over the radio.

According to the document, teams can inform a driver about concerns with their vehicle but “any message of this sort must include an irreversible instruction to enter the pits to rectify the problem or to retire the car”.

The fresh directive also underlined that the radio restrictions will not apply if a car is in the pitlane, whereas earlier they kicked in as soon as the vehicle left the garage.

Ferrari’s Vettel, 29, said curbing radio transmissions was the wrong way to go, given the technological complexity of modern-day cars, and called for the restrictions to be lifted.

“It’s not our mistake, as in the drivers, that the cars are so complicated these days that they need a big manual and a steering wheel full of buttons to operate it,” the four-times world champion said.