By Andrew Benson
BBC Sport at Silverstone
Walking into a Formula One paddock for the first time in nearly a year, on the surface things look much the same as ever.
The trucks that transport the teams' cars around Europe are in the same neat line; there is one team motorhome that is trying - and succeeding - to outdo all the others in terms of ludicrous ostentation.
Michael Schumacher arrives at Silverstone, where he won last year
This year it's Red Bull, whose "Energy Station" is three stories of chrome curves and glass, takes between two and three days to erect, and looks like a five-star Dubai hotel has crash-landed in Northamptonshire.
In the walkway between the polished trucks and motorhomes, people are milling about, chatting in small groups under a typically leaden sky.
But this appearance of peace, well-being and tranquility is a facade.
And one does not have to dig too far below the surface for it to be clear that the atmosphere in F1 is poisonous in the extreme.
Jarno Trulli is searched as security is stapped up following Thursday's bomb attacks on London
Thursday's bomb blasts in London ensured that, for once, the division that is threatening to tear the sport apart was not the first thing on people's lips - and may even ensure it is kept in the background all weekend.
But the F1 paddock is a notoriously insular and self-regarding place, and this split - antagonised by the open wounds left by the fiasco at the United States Grand Prix last month - remains the dominant theme.
The seven teams who refused to race at Indianapolis because Michelin could not guarantee the safety of their tyres are still fuming at the intervention of Max Mosley, president of governing body the FIA, to prevent a compromise that would have allowed the race to go ahead.
More seriously, the events in the US last month have deepened the fracture between the two camps in F1 - a fracture that looks ever less likely to be healed.
Two separate camps; two visions of the future; no apparent prospect of an accommodation
On one side of this dispute are Ferrari and Mosley, who have agreed with F1 commercial supreme Bernie Ecclestone a deal that has committed the world champions to F1 beyond 2007, when the teams' existing contracts run out.
On the other side are the rest of the teams.
Two separate camps; two visions of the future. No apparent prospect of an accommodation.
And, many believe, no lessons learned from the Indy farce.
If a similar situation happened again, no-one on the "rebel" side believes Ferrari would act any differently and put selfish interests aside to ensure a race went ahead.
Meanwhile, Mosley continues to antagonise important members of the F1 fraternity. Deliberately or not, no-one knows - although everyone believes it is.
This week, it is the drivers whose backs he has got up, cancelling a meeting at which they were to discuss safety on Friday because David Coulthard had criticised many of the rule changes Mosley has introduced in recent years.
Mosley is at the centre of the divide threatening Formula One
The drivers normally like to keep their heads down and handle such situations behind closed doors for fear of retribution; this time, they were annoyed enough to publish a letter they had sent to Mosley to express their concerns that he was disregarding their input on safety.
As one leading driver told me: "If the drivers are getting involved, you know things are getting serious."
On a macro scale, this dispute could not be more serious for the future health of F1.
Mosley has published a set of rules he wants to see introduced in 2008 - a low-tech vision of F1's future.
But the nine teams - and particularly the ones supported by the major car manufacturers - do not see the logic in having an F1 that would be several seconds a lap slower than
a GP2 car, the category that is supposed to train drivers for F1.
Mosley has said he wants input from those in F1 into his ideas on rules, but the "rebel" nine believe he will only listen to those who have committed to F1 beyond 2007 - in other words, only Ferrari.
F1 stares into an abyss and no-one in it seems to know how to stop it stepping out over the edge
The nine see this as further favouritism of Ferrari, who have already secured a financial deal that is strongly skewed their way in the future.
In that new deal, according to senior figures on the "rebel" side, Ferrari could finish last in the world championship and still earn 40% more money than the team who win the title.
Meanwhile, the manufacturers are producing their own set of rules by which they want F1 to run in the future.
And if they do not get what they want, they say, they will set up their own championship in 2008.
Everyone involved on both sides recognises that a split into two rival series would be a disaster.
But the only way to stop it happening is for the two camps to sit down and talk. And they can barely stand being in the same room as each other.
So F1 stares into an abyss and no-one in it seems to know how to stop it stepping out over the edge.