Olympic silver medallist Lizzie Armitstead has withdrawn from the Great Britain team for the UCI Road World Championships road race on Saturday due to illness, British Cycling have announced.
The 23-year-old from Otley won Britain's first medal of the London 2012 Olympics and was poised to lead the team in the 129-kilometre road race in Limburg, Holland.
A statement from British Cycling read: "Lizzie Armitstead has withdrawn from the UCI Road World Championships on Saturday due to illness. The team have decided not to call in a reserve rider at this stage."
Britain had qualified the maximum six riders for the road race, but Armitstead's absence means a five-strong team will take to the start line.
Emma Pooley, who finished fourth in the time-trial on Tuesday, could lead the squad on an undulating course, while 2008 Olympic champion Nicole Cooke is likely to be given a free role.
Pooley and Cooke are joined by Sharon Laws, Katie Colclough and Nikki Harris.