Yes, they are. Young workers aged 16 and 17 are entitled to 12 consecutive hours of rest in any 24 hour period under the Working Time Regulations.
Under the same Regulations young workers are also entitled to a rest period of no less than 48 hours in each seven day period, compared to 24 hours in each seven day period for an adult worker.
Just One More Click: Doggy drama about staying safe online at work.