It may be Franz Tost’s swansong season in F1 but the veteran team principal is still unafraid to make the big calls when required.

At the Saudi Arabian Grand Prix in March, Tost pulled no punches in assessing the team’s start to the year in Bahrain following pre-season testing and the opening grand prix at the Sakhir International Circuit.

With his typical no-nonsense style, he singled out the engineers on the team for over-promising and under-delivering.

“The engineers are telling me that we are making some good progress, but I don’t trust them anymore,” wax Tost’s eye-opening remark at the time. “I just want to see the lap time because this is the only thing that counts.”

As to whether he was serious about his comment, he added: “In the winter months they told me the car is fantastic, we’ve made big progress.

“Then we come to Bahrain and we are nowhere. What should I say?”

Seven weeks on, and speaking ahead of this weekend’s Miami Grand Prix, Tost has confirmed action has been taken with regard to one of those engineers in particular.

Despite a degree of progress with the AT04, notably following the upgrades applied ahead of the Azerbaijan Grand Prix, Tost was asked whether he continued to stand by his remark.

The Austrian, who will leave AlphaTauri at the end of the season and be replaced by current Ferrari sporting director Laurent Mekies, again did not hide the truth.

“The person I didn’t trust anymore is out, as you can imagine, and the others I trust,” said Tost. “Totally easy. And they do a good job.”

Tost and AlphaTauri have since refused to elaborate on the individual concerned, although the head of aerodynamics Dickon Balmforth has been mentioned in some quarters.

The suggestion is Balmforth left AlphaTauri soon after the start of the season, tying in with Tost’s initial comments in Saudi Arabia.