A system and method for restricting public access to a mobile telecommunications network in order to prevent congestion. The system and method are particularly useful in situations where the number of end users exceeds, or is likely to exceed, network capacity, for example in emergency situations or for large public gatherings, such as sporting events or New Years Eve celebrations. The system and method disclosed uses filtering by network elements, such as the base stations and MSCs. In particular the system and method can filter low data messages, such as SMS, from more demanding services, such as voice calls, so that all low data messages are transmitted, while the more demanding services are terminated, unless special conditions are met.