The final week of testing got underway this morning at Barcelona, and while Carlos Sainz got proceedings underway just moments after the lights went green, Lewis Hamilton and Sebastian Vettel were right behind, eager to continue their preparations for Melbourne and beyond.

While others completed a handful of installation laps, Hamilton and Vettel were soon posting times on a day that sees eight of the teams follow Mercedes example and run both drivers, Haas being the only exception, while Alfa Romeo, where Robert Kubica is on duty, once again being the only team to run a reserve driver.

As ever, flo-vis and aero rakes were much in evidence, Ricciardo's Renault sporting sensor gates both front and rear.

Almost an hour into the session, Grosjean was the third driver to post a time, followed, shortly after by Ricciardo.

A number of teams have updates here, the most noticeable being a new front wing on the Williams and a new rear wing on the Ferrari.

As more names appeared on the timesheets, Kubica had a spin in the final corner, no doubt due to the lack of grip offered by the chilly conditions.

In anticipation of the Dutch Grand Prix and its infamous banked corner, Pirelli has supplied two sets of a prototype C2 tyre to each of the teams, Hamilton being among the first to give the proposed rubber a go.

As most continued to rack up the lap count and improve their times, two hours into the session the Honda-powered cars had only completed 3 laps between them, Albon having managed 1 lap and Gasly 2. While the Red Bull was understood to have a suspension issue, which meant the removal of the floor and therefore the shutters being pulled into place, it is thought that Gasly's engine had somehow been dislodged.

Meanwhile, in the McLaren garage, Sainz' car was up it stands, before being hidden from view as the shutters there were pulled into place also.

A strange spin for Vettel in T8 which saw gravel spread across the track meant the first red flag of the week, and once the session resumed Hamilton wasted no time in improving on the C2s despite a very scrappy lap.

A run across the sausage kerbs for Latifi brought about the second red flag of the day, but when the all-clear was given Albon and Gasly were among the first out.

As the Honda-powered drivers posted their first times of the week, Hamilton, who was nearing the end of his race sim, brought his run to an end 5 laps early after running over those infamous kerbs.

With 40 minutes of the morning remaining, Kubica, on the C5s, went quickest with a 16.942, the Pole echoing Kimi Raikkonen's headline grabbing effort of last Thursday.

Back on track, Hamilton subsequently improved, as did Albon and Gasly. The Thai driver looked set to be heading into the break - when he will hand over to Max Verstappen - in second, but at the death Gasly posted a 17.540 to edge him out by 0.010s.

All in all, an uneventful morning, despite the red flags, and while Hamilton and Vettel led the way in terms of lap count, though second and third on the timesheets, AlphaTauri and Red Bull will be seeking to make use of every available minute this afternoon.

Racing Point's pace was good, despite the relative lack of laps (43), as was the case at McLaren, while Haas remains in a worryingly lowly position.

Check out our Wednesday gallery from Barcelona, here.