Learner motorcyclists face losing the right to ride unaccompanied under Government plans, according to the Motorcycle Industry Association (MCI).
Plans to scrap the right are likely to be revealed later this month, the Association fears.
It would leave learners only allowed to ride while accompanied by an instructor and deny thousands of daily transport.
The proposals are expected to be included in a consultation on new Europe-wide laws set to make it more difficult to gain a motorcycle licence from 2013.
The new rules will raise the minimum age for Direct Access – a single practical riding test for access to unrestricted bikes – to 24.
Riders who take the standard route will be subject to power limits for four years, two at 15bhp and 125cc and two at 47bhp.
The consultation will be on details of the new regime, such as whether learners should have to take an extra test or complete additional training to progress from 15 to 47bhp.
An MCI spokesman said: “The consultation may also propose that learner motorcyclists should lose their right to ride unaccompanied on L-plates.”
He said the Association had warned Transport Secretary Lord Andrew Adonis that “these measures would be extremely damaging to the industry and the vitality of motorcycling in the UK”.