The Broom Wagon - a Tour de France rider's biggest fear.

Six stages down and eight riders are already at home or on the way home. The latest rider out, at the time of writing, is Astana team leader Janez Brajkovic. He had the misfortune to crash with just 10kms remaining of yesterday’s stage to Montpellier.

Visibly shocked and shaken, he courageously rode to the finish only to be ordered by the doctors to abandon the Tour. A very large and deep wound to his knee was considered to be far too serious for him to continue.

It was this latest withdrawal from the race that made me think at least he didn’t have to undergo the at times heart-breaking experience of having to climb into the dreaded ‘Broom Wagon’ - or, in French, the ‘Voiture Balai’. This literally translated as the ‘Sweeper Up’, and it very often has a broom stuck to the front or back of to easily identify it.

The Voiture Balai was introduced to the Tour de France in 1910, and has been a permanent fixture ever since. It is in every pro race in the world: single day or multi-stage.

Picture: US rider David Zabriskie leaves the broom wagon as he abandons the 2005 Tour de France.

At some time in their career every rider will experience the Broom Wagon. Sometimes it is through necessity - either from illness or a fall - or just from the fact that’s not been a good day and they’re well off the pace. Sometimes it’s a relief to get on board, while at others it’s a real disappointment. But the worst time to be swept up is during Le Tour.

I’ve been there. I defy any rider to say he hasn’t shed a tear at climbing into the Tour Broom Wagon. Maybe not immediately but at some time in that journey to the finish, behind the race at the back of the convoy, the reality will hit home. You would rather be anywhere in the world than in that bus.

You climb off the bike, followed by the horrible moments when the Commissaire takes off your race numbers, and the assistant wheels away your bike. It’s an experience that you will never forget.

I was asked the other day if it’s the walk of shame. Maybe there is the odd exception, but no it’s not: nobody abandons the Tour without good reason. But that doesn’t make it any easier.

Coverage of the Tour de France continues from 3.30pm on Friday 5th Julyon 5 live Sports Extra. Download the BeSpoke podcast for daily analysis from commentator Simon Brotherton and the team.