Stroll returns to the pits. He reports contact with the barriers, and he's in the garage for precautionary checks.
Lawson? What was you doing in second place? Highlighting how the times are falling, the Racing Bulls driver briefly goes to P2, but Norris knocks him down a place after going fastest with a 1m14.375s.
Norris narrowly avoided the wall with a snap of oversteer on the exit of the swimming pool. He goes third fastest, but here come the Red Bull and Mercedes pairs.
These times are tumbling big time, as Hamilton puts in a 1m14.390s. An error at the final corner saw him need a second stab at the brake pedal, so it wasn't his fastest final sector, but the rest of the lap was mighty.
Oh no! Perez now reports his front left brake is catching fire. He returns to the pits but this is now a major safety issue for Cadillac.
Mercedes and Red Bull are enjoying a leisurely start to the session, with all four drivers remaining in the pits for the moment.
Bottas is reporting smoke from his front right brake. It's the same brake that Perez suffered from in FP2. He suggests he won't use the brakes anymore, in order to prevent a repeat of his team-mate's fire.
A 1m15.246s from Hamilton, but Leclerc goes slightly quicker with a 1m15.184s. The times are notably slower than Friday, but as the track rubbers in, this will change.
As expected, soft tyres are the order of the day. It would be somewhat of a surprise if we saw anything other than soft rubber at all today.
We won't get to say this often, so let's enjoy it, but Bottas is setting purple sectors everywhere. Hamilton sets the first time, but Bottas bests it with a 1m21.115s.
Ok, they were prep laps, but a Cadillac is fastest!
But after 30-odd seconds, here comes Hamilton. Bottas, Leclerc, and Stroll follow the Ferrari pace-setter out.
Green light, and FP3 begins. No one rushes out.
Five minutes before the lights go green. This hour could make or break a weekend.
Secondly, McLaren breached the strict curfew rules last night in order to complete repair work on Lando Norris' car, which crawled to a halt in FP2. The repairs were described as "extensive" by the team, but all appears ready for the coming hour of action.
A couple of bits of news from overnight for you. First, we send our best wishes to Ferrari team principal Fred Vasseur, who will not be at the track today after being admitted to a local medical facility with an unspecified illness.
Get well soon Fred.
Good morning and welcome to Monaco, where the chaos has already begun, with a time-certain F3 race after lap one chaos at the hairpin saw multiple retirements - nothing new for this particular venue!
The F1 action will get underway in just under 15 minutes, with the sole focus on a crucial qualifying, which sets the tone for Sunday more than at any other track.

