We all know plastic bags damage the environment, but what about the harm they can cause if you're driving a team director's car in a bike race? "Sky, that is the last warning!" squawks the Tour of Oman's chief official over the Sky team car's race radio as sports director Servais Knaven bowls along at 60kmh with rider Russ Downing and his bike in tow.
Downing's rear sprocket has just come off worse in a close encounter with a stray plastic bag. Sky's mechanic tried to fix it – leaning out the window, waving a pair of scissors as he works face down, centimetres from the tarmac whizzing beneath him – but it's no good, the bag is jammed in.
One quick bike change later, and though race officials almost always turn a blind eye to riders clinging on to team cars and being towed back to the peloton, the message behind the warning to Knaven is clear: "You can only push it so far."
But, as The Independent on Sunday witnessed during a fascinating day in the Sky car, seeing what they can get away with is precisely what all 20 team directors spend up to five fraught hours a stage doing.
Former pros almost to a man – the Dutchman Knaven has just completed a 16-year career, with the highlights being victory in the Paris-Roubaix and a Tour de France stage – the directors know how important motorised support is for riders.
But with no race radios – riders drift to the back of the pack and raise their hand if they want something – it's a demanding task. As soon as a rider reaches the team car window, a stream of water bottles, gels and energy bars are passed out for the entire team at top speed along with tactical instructions. In return, riders provide reports of what it is really like among the bobbing sea of posteriors and frantically pedalling legs we can see a few yards ahead.
On stage three of the Tour of Oman last month, set against a stunning backdrop of semi-desert, shadowy mountain ranges and the glittering Arabian Sea, Sky's pointman is Ian Stannard, a lanky 24-year-old from Chelmsford. "Keep close to the front, eh, Ian?" says Knaven as he steers with his knees and hands over a dripping set of water bottles, "we've got Kurt [Asle Arvesen] working on the front, but there are lots of crosswinds," meaning that the pack could split at any point.
Whether Knaven's orders get passed on will depend largely on Stannard's ability to find his team-mates in a 180-strong pack. Not to mention whether everybody on the team understands the English bawled at them in a sweaty, swearing pack all travelling at high speed. Knaven admits that communication is hard work. "It's like there's a wall, you know?" he muses. "What we have to find is ways of getting through that wall."
A recent ban on internal team radios has made it harder for directors to communicate with riders. It is a controversial issue with questions of safety, riders taking their own initiative rather than dumbly following orders through their earpieces. Knaven is not in favour of the ban, pointing out that it would "be terrible if a rider lost a race like Paris-Roubaix because he couldn't communicate with his director".
With stakes so high and time for communication at a premium, team cars are crammed to the gunwhales with supplies. Up to 100 bottles in giant coolboxes and two sets of spare wheels barely give mechanics breathing space in the back seat, while a set of spare bikes is lashed to the roof.
But it's the minor details that make the difference. Sky pride themselves on their "marginal gains" – a phrase borrowed from British Cycling's all-conquering track squad, which team principal Dave Brailsford also runs – and during the five-hour stage through the bleak beauty of Oman's northern deserts there is plenty of time to find out what some of them are: colour-coded water bottles for faster identification (blue for water, orange for energy drinks), specially adapted sticking plasters for high-speed first aid, and ultra-detailed printouts of maps with the all-important wind direction pencilled in.
This last aspect proved crucial in Oman. On the main mountain stage, forewarned by Knaven that morning, Sky's riders took advantage of a change in road and wind direction to move ahead collectively and split the pack. One indirect result was that Sky's Edvald Boasson Hagen moved up to second place overall.
The order of the team cars in the following convoy is also hugely important. Decided by the riders' ranking in the overall classification and with numbers stuck to the car's bumper indicating a position in the pecking order, it is not unheard of for squads to slap on fake number stickers in order to gain a few places.
However, there is little that a team car can do to decide how their riders will react in the crucial final hour. As the pace rises in the closing kilometres, we roar past Stannard, now weaving all over the road in exhaustion, then Knaven sticks his thumb out of the window to signal his approval to the team workhorse Arvesen, who has also been dropped.
The crowning irony is that with no radios, Knaven and the other directors are last to find out who has won the stage. Like stokers in an ocean liner, their view is strictly limited to the race's engine room. It's only when the Sky team car inches through the finishing area and passes a horde of Rabobank riders in a session of back-slapping and hugging that Knaven glumly concludes it's another team, not Sky, who will be standing on the podium this time. But there will be another opportunity tomorrow – and, hopefully, no stray plastic bags.