Mercedes' James Allison clarifies brake problems during Azerbaijan Grand Prix practice

Mercedes technical director James Allison has revealed the cause of brake issues experienced by Lewis Hamilton and George Russell during practice for the Azerbaijan Grand Prix.

The session was disrupted and ultimately shortened, as Parc fermé was enforced after only one hour, as part of the new sprint format for the weekend. This will involve two qualifying sessions, a 100km sprint and the Grand Prix.

Both drivers complained of braking issues, with Hamilton suggesting that the pedal felt long, and Russell echoing his concerns.

Allison explained to media that Hamilton had experienced issues with the brake-by-wire setting, which had been set to "passive" mode. Allison said, "So he just had to come in and do a switch setting to get that back into good shape. I think in George's case, the brakes were just a bit spongy so that will all get sorted out for the next session."

The changes to the sprint format were confirmed at the F1 Commission meeting earlier in the week. Allison, who returned to his role as Technical Director just 20 months after switching to become Chief Technical Officer, welcomed the new format. He said, "although it feels loaded with fear and jeopardy, the fact you get into the paying end of the weekend that much quicker, there are four scary sessions instead of two - there is more fun for all of us."

The new format was introduced to encourage more exciting races, and there is optimism that it will succeed. Allison said, "free practice is ace because you get to find out about the car, but I think all of us like the adrenaline of the qualifying and the races more than the practice."

Hamilton could manage only 11th for Mercedes, 1.5 sec back off the pace with team-mate George Russell also struggling, taking the chequered flag 17th of the 20 runners in the practice session.