Cycling: William Fotheringham discovers unwritten rules that govern the Tour's cyclists

When almost 200 cyclists are unleashed on to the roads of France, etiquette might seem a minor consideration.

But when the 23-year-old Frenchman Anthony Geslin went clear of the peloton at the feeding area on Tuesday, he was breaking an unwritten rule: the point where the cyclists gather their small cotton bags of energy food is sacrosanct. "Grilling the ravito", as cycling slang has it, is strictly a no-no.

This is nothing to do with the fact that lunch is a sacred ritual in France, but simply because collecting the musettes is an operation best done at a sensible pace. To illustrate the point, there was a crash in the zone de ravitaillement (refuelling zone) on Tuesday after Geslin's attack.

Like any community, the peloton has its rules. There is the Tour's rule book, restricting activities such as urinating in public and where to collect bottles, and there are the unwritten conventions that simply make life safer, more pleasant and remunerative for the cyclists.

Not riding dangerously is the most obvious, although the sprinters interpret that one extremely loosely. If the ravito is sacrosanct, so are the collective moments when a large group of riders - usually led by the yellow jersey of the day - collectively decide to suspend hostilities on a quiet stretch of roadside and empty their bladders. The occasion on which Laurent Jalabert lost the yellow jersey in 2000 because a group of riders failed to respect this rule is now known as the pisspot revolution.

The worst crime in the unwritten rule book, says Scottish cyclist David Millar, is "attacking a yellow jersey when he's crashed or punctured". The maillot jaune is accorded great respect: it is the convention that if the wearer wishes to glide forwards in the group, his fellows will slip aside or, if the field is lined out, he will be permitted to enter the string.

The rules revolve around mutual respect, which is why Lance Armstrong famously waited for Jan Ullrich when he crashed on a Pyrenean descent two years ago: Armstrong would expect the same of the German.

It is also why when two cyclists have escaped together, and one takes the yellow jersey at the stage finish, he will permit his co-escapee to have the stage win. The tactic that arouses the most ire is "wheelsucking": feigning fatigue in a breakaway, then finding your strength in the finish sprint.

"There's less and less respect in the bunch," says Millar, shaking his head at the antics of what he terms "the younger generation". He explains: "There are fewer and fewer windows of opportunity to get clear of the bunch, fewer times when the pace is slow, so a small minority will take advantage."

Punishment is collective: verbal warnings, then the mistrust and retribution of the peloton for repeat offenders, which is why Geslin may not be permitted to show his face again on this Tour. His lunchtime break may cost him dear.