Bradley Wiggins has sparked a massive debate in the world of cycling, after suggesting that it should be compulsory for bike-users to wear helmets.
Many cycling campaign groups and charities have made it clear that they don't agree with the Olympic time trial champion.
Cycling charity CTC tweeted: "Mandatory helmets would not be helpful - everyday cycling would collapse and there would be no change in driver attitude/behaviour. "
They continued: "Not sure it is useful to give so much credence to views of gold medallist on road safety - how about Steve Redgrave on the Costa Concordia?"
The London Cycling Campaign also weighed in, saying: the "Helmet debate is [a] damaging diversion from real issues".
And Carlton Reid, the executive editor of cycling website Bike Biz, slapped down the idea too.
He said: "Bicycle helmets are designed for low speed crashes from head height to the ground and offer next to no protection in smashes with motor vehicles.
"However, this fact did not prevent Bradley Wiggins urging helmet compulsion for all cyclists, a measure that many studies show would offer no whole-population health benefits."