Should there be an age limit on purchase of energy drinks?

Experts advising the government have said there is not enough scientific evidence to warrant a ban on the sale of energy drinks to children. But the Science and Technology Committee said concerns in society, and evidence from teachers, could "justify a ban." What do you think - should there be an age limit on the purchase of energy drinks? Stephen got the views of commentators Heidi McAlpin & Dave Atherton.