If we rely purely on this morning's session, then Romain Grosjean is the main threat to Sebastian Vettel this weekend. Having lost tracktime during both of Friday's sessions, the Frenchman was on fierce form this morning, possibly motivated by the thought of being number one at his team next year - assuming they retain him and assuming they don't hire an established driver, say Hulkenberg or Massa.

His current teammate, on the other hand, was woefully off the pace, and it isn't clear why, far be it from us to suggest that he's sick of the 'cheque's in the post' stories.

While the Mercedes duo and Mark Webber kept Vettel honest yesterday they were off the pace this morning, though this afternoon's conditions - which are very similar to yesterday's - should see them close the gap again.

That said, the Australian, unlike his teammate, doesn't seem comfortable with the option tyres (supersoft) and to make matters worse mechanics have been working on his car since FP3.

After a lull in Belgium and Italy, tyres are back in the news again this weekend, tyre wear an issue for several teams most notably Ferrari.

Behind the 'usual suspects', McLaren appear to be the best of the rest, Force India still suffering following the changes made to the tyre compounds a couple of races ago. Though one feels sympathy for the Silverstone outfit, this isn't the first time the rules have been changed mid-season to the detriment of some and benefit of others.

Being a street circuit it's been hard to get a real feel for who's hot and who's not this weekend, nobody willing to push that little bit harder just in case it results in an accident that keeps them out for the remainder of the session. That sort of stuff can wait for the return to 'proper' tracks, though a few, including Webber, have ridden their luck this weekend, getting more than a little friendly with the unforgiving barriers.

That said, Williams is off the pace while Toro Rosso and Sauber, still celebrating its Monza result, could spring a surprise.

As with any street circuit pole will be important therefore Vettel will very much want to be up front. At the same time, it's wroth noting that teammate Webber has been doing lots of practice starts from the pitlane this weekend.

Gut feeling has a Mercedes on pole however, Sebastian has to be favourite to take the race win.

Tyre options are medium (prime) and supersoft (option), as opposed to soft and supersoft. The difference between them around a two seconds though it is the option that will be favoured during the race, the primes having a "short life expectancy", certainly as far as some drivers are concerned.

There are two DRS zones this year. The first is on the pit straight - with activation on the approach to Turn 22, while the second runs between Turns 5 and 7 - with activation just after Turn 4.

With the removal of the Singapore sling chicane and the resurfacing of the track, times are considerably faster than in 2012. Indeed, Hamilton insists the track is not "twice as grippy".

In the minutes leading up to the start of the session there is talk of Raikkonen suffering a back pain scare, maybe Lotus has finally comes up with his wages, paid him in cash and he's stuffed it in his overalls pocket unwilling to take the risk and leave it in the motorhome. Lotus subsequently tweets a pic of the Iceman 'in situ', admitting that he does have a "bit of back pain" due to the "bumpy old track".