Ahead of today's sole practice session, the air temperature is 28 degrees C, whilst the track temperature is 47 degrees. It's hot and sunny.

Lewis Hamilton was the pace-setter in both of yesterday's sessions - hardly the first time you've read that line - ahead of teammate Nico Rosberg, and, in FP2, three other Mercedes-powered cars.

That said, Roberg's second session was cut short following an unspecified engine failure.

As expected the Renault powered cars are struggling, Max Verstappen, who sat out most of FP1 with a technical problem, the highest placed 'Renault man' in seventh.

Sebastian Vettel could only manage eighth, as both Ferraris suffered MGU-K issues.

Indeed, based on the evidence thus far, one has to say that behind Mercedes, and sure to use its usual canny tyre strategy, Fore India looks to be best of the rest.

Whilst Hamilton is delighted with the Baku City circuit, thus guaranteeing a place at the very top of Bernie Ecclestone's Christmas card list, the FIA carried out a number of modifications to the circuit overnight.

The kerbs at Turn 6 and 12 have been removed and paint be used to mark out the track limits, while work was also carried out on the section between Turns 12 and 15, with particular attention to Turn 13.

At the same time, the line marking out the pitlane entrance has been moved back and to the left after drivers complained that undulations on the final straight made it almost impossible to see the line marking the pit entrance. A new pit entry sign has also been put in place.

Nonetheless, we can expect incident aplenty as the weekend progresses, this morning's GP2 race hiving witness a crash that eliminated 5 cars at the start, necessitating a re-start, and only 10 of the 22 starters seeing the chequered flag.

The lights turn green and once again Gutierrez leads the way, followed by Grosjean, Rosberg, Wehrlein and Ericsson. In moments there are 14 drivers on track.

Unlike yesterday, there are quite a few drivers on the harder medium rubber, though a few are on supersofts and a couple of others on softs.

Oh dear, a loose piece of guttering in the pitlane has damaged the sidepod on Bottas's car. "Some drain cover or something came off in the pitlane," says the Finn.

The FIA's Jo Bauer heads to the spot and places a marker cone at the scene of the offending gutter.

It's not all bad for Williams however, Massa has gone quickest (48.346), ahead of Nasr, Ericsson and Haryanto.

"It's ok," tweets Mercedes, "an orange cone fixes everything..." Indeed.

Perez is one of the first to fall foul of T1, as a marshal is placed in the pitlane to warn drivers of the errant gutter.

For a brief moment it's a Force India 1-2, Hulkenberg leading the way with a 46.877, but then Ricciardo posts 46.685.

Twelve minutes in and all but Sainz have made an appearance.

A 46.848 sees Verstappen make it a Red Bull 1-2 but Perez spoils the party when he splits the pair with a 46.825.

Vettel posts 48.978 to go 12th, as Rosberg heads down the pitlane.

His first lap sees the championship leader posts 53.669, improving to 45.558 next time around.

Kvyat is off at T4 whilst Massa spins at T15. The Russian reverses out of the escape road, giving concern as to what sort of problems could arise if this happens tomorrow.

Hamilton's first lap is a 53.139 however, next time around it's a far more sensible 45.675, to go second by 0.117s.

Massa clouts the wall at T15 after losing the rear. He is able to continue having not incurred too much damage, and returns to the pits.

A 46.710 sees Button go fourth, McLaren continuing to look promising here.

Bottas is out of his car and it looks very much as though his session is over.

A massive slide for Hamilton in T16, the Briton making it look so easy.

Top speed through the speed-trap is 330km/h (205 mph) posted by Rosberg, ahead of Perez, Hulkenberg, Hamilton and Ricciardo (323 km/h / 200 mph).

As Perez goes off at T15 bringing out the yellow, Raikkonen reports: "I have some issue. I have no power coming out of the corners". Sure enough he heads back to the pits... very slowly.

Vettel posts 45.694 to go third, 0.259s off Rosberg's pace.

As Magnussen goes off at T1, Palmer complains that he has a sudden loss of grip and has a "strange feeling at the rear".

With 19 minutes remaining, and attention soon to switch to qualifying, it's: Rosberg, Hamilton, Vettel, Massa, Ricciardo, Hulkenberg, Button, Kvyat, Perez and Verstappen.