The Derby order lasts for four months

The new anti-social behaviour order comes into effect on 1 December and runs until the end of March 2005.

Under a previous order the number of violent crimes in the city centre fell by 17%, a police spokesman said.

The order allows uniformed officers to disperse people if they are causing or likely to cause alarm or distress to members of the public.

During the previous period, more than 200 groups were moved on and 15 people arrested for failing to obey the order.