The Manxman, who was bidding for a maiden yellow jersey, looked to be in a great position as Omega Pharma-Quickstep led the way on to Parliament Street.
However, after an audacious attack by Fabian Cancellara (Trek Factory Racing), Cavendish found himself jostling for position with Simon Gerrans (Orica-GreenEDGE) as the sprinters chased Spartacus down.
Leaning into Gerrans, Cavendish brought both himself and the Australian champion down – suffering a separated shoulder in the process – and apologised for his role in the drama.
“I’m gutted about the crash today,” he said. “It was my fault. I’ll personally apologize to Simon Gerrans as soon as I get the chance.
“In reality, I tried to find a gap that wasn’t really there. I wanted to win today, I felt really strong and was in a great position to contest the sprint thanks to the unbelievable efforts of my team.
“Sorry to all the fans that came out to support – it was truly incredible.”
Omega Pharma-Quickstep confirmed the sprinter had suffered ligament ruptures and an AC-joint dislocation, and will take a decision on his participation in stage two in the morning.
With Cavendish having crashed out, it left Marcel Kittel (Giant-Shimano) to pull on the yellow jersey for a second consecutive year.
And the German fast man – who paid tribute to the huge crowds who were out lining the route – was quick to praise the work of his team-mates.
“It was a really special day today – the supporters lining the roads were incredible,” he said. “I am so proud and this means so much to me that we made it happen.
“The jersey is for the team after the job they did today and all the fans out there supporting us also deserve a slice.
“We worked so hard for it – everyone pulled just as they should and even with a slight reshuffle in the sprint formation at the end we got it perfect.
“John [Degenkolb] and Koen [De Kort] pulled through the last few hundred metres of the lead-out and then I had to go for it as Sagan launched.
“We got it right again today and it was a real team effort. It’s a special day.”
Photos used with kind permission of Simon Wilkinson and swpix.com.