One of the main reasons why front brake protectors were finally made mandatory for the 2012 MotoGP season can be traced back to this shocking incident at Catalunya in 2006.

The accident began when Sete Gibernau tangled with factory Ducati team-mate Loris Capirossi as they braked for turn one; the Spaniard being sent flying over the handlebars after contact was made with his front brake lever (see below for more pictures).

That impact then caused world championship leader Capirossi to veer sideways into Marco Melandri - with the two Italians falling and hitting the back of Dani Pedrosa and John Hopkins ahead of them, meaning a total of six riders and machines tumbled into the gravel trap at high speed

When the dust had cleared Gibernau was amazingly able to walk away, but both Capirossi and Melandri were lying motionless. Capirossi soon regained consciousness, while Melandri was carried off on a stretcher.

Melandri was later diagnosed with a collarbone dislocation, mild concussion and a multitude of minor injuries. Capirossi suffered chest injuries, while Gibernau required surgery for a fractured collarbone.

In an scene that summed-up Gibernau's luck at Marlboro Ducati, the ambulance taking him to hospital was involved in an accident with a bus just 50 metres from the hospital entrance.

Amazingly, Capirossi - tied with Hayden at the top of the standings heading into the seventh round - and Melandri (who had been third in the championship with two wins) were back on track just days later at Assen and scored points in the race.

But with hindsight their 2006 title hopes ended in the Catalunya gravel.

The restarted Catalan race saw Yamaha's Valentino Rossi take victory over title rival Nicky Hayden (Honda), while former champion Kenny Roberts Jr put Team Roberts on the podium in third.

The fifth round of the 2012 MotoGP World Championship takes place at Catalunya this weekend.