"I see lots of people in bike accidents and these flimsy little helmets don't help."
Mr Marsh said that he had ridden his bike for 40 years, wearing a cowboy hat, and had only fallen off once.
In Britain, lights and reflectors are a legal obligation after dark, and reflective jackets are increasingly common. But helmets are not compulsory in the UK, unlike in New Zealand, Australia and parts of the US, yet the Government encourages cyclists to wear one.
Research by Dr Ian Walker, a professor of traffic psychology at the University of Bath, showed that motorists drove around 8cm closer when overtaking cyclists with helmets.
He suggested that drivers think helmeted cyclists are more sensible, predictable and experienced, so do not need to give them much space when overtaking.
Non-helmeted cyclists, especially non-helmeted women, seem less predictable and experienced so motorists give them more room.
However, Mr Marsh's comments are likely to anger cycling safety campaigners, who believe that helmets provide essential protection on Britain's busy and narrow roads.
A Department of Transport study has shown that helmets could prevent 10-16 per cent of cyclist fatalities.
Angie Lee, chief executive of the Bicycle Helmet Initiative Trust said: "I hope he is going to take responsibility for the cyclist who gets injured because they take their helmet off following his comments.
"My advice would be the same as the department's, which is that helmets have a place in protecting the head."
Head protection
Many patients who have been involved in bike accidents have been wearing helmets that were "too flimsy" to be beneficial.
Evidence suggests that helmets may put cyclists at greater risk.
Research shows that drivers get around 8cm closer to cyclists who wear helmets because they perceive them as safer.
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