Yes. The DSE Regulations say that employers "should allow their employees time to take breaks away from the workstation and telephone, and the accompanying mental and physical stresses”.
Both the length of break times and their frequency are equally important. 'Breaks' can range from doing other non-computer-related tasks to completely stopping work. The DSE Regulations do not define 'break time' in terms of minutes every hour.
The Working Time Regulations 1998 are also relevant. Regulation 8 says that where the pattern of work puts the health and safety of any worker at risk, especially if work is monotonous or the work rate is predetermined, the employer must ensure workers get adequate rest breaks. This is on top of the basic rest break entitlement under the Working Time Regulations of 20 minutes away from the workstation after working six hours in a day.