Manxman Cavendish and Spaniard Izagirre were both involved in a crash as the race wound its way through the testing and narrow roads into the Lake District from Prudhoe to Hartside Fell.
Cavendish can be seen talking animatedly to Izagirre at the roadside after both riders had picked themselves up from the incident. Izagirre then walks off, and both riders pick up their bikes and continue.
It is unclear how the incident happened.
Team Sky's Wouter Poels went on to win the stage, which featured an ascent up Hartside Pass. Poels passed Edvald Boasson Hagen (MTN-Qhubeka) in the final few hundred metres of the stage to take the win, with Boasson Hagen putting himself into the race lead.
The 2015 Tour of Britain continues today with a stage from Stoke-on-Trent to Nottingham. The race concludes in London on Sunday, September 13.
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