MTPAS (Mobile Telecommunication Privileged Access Scheme) is a British procedure for prioritising access to the mobile telephone networks for privileged persons (members of emergency services as designated at a local level). It replaced ACCOLC in 2009. MTPAS is only available to Category 1 and 2 Responders (as defined in the Civil Contingencies Act 2004) and partner organisations which directly support them at the scene of an emergency incident. Using an agreed protocol, the Police Gold Commander, in charge of the response to a major incident, notifies all network operators that a major incident has been declared and activation is then their responsibility. As a result of the incident, mobile telecommunications networks may experience an abnormally high concentration of calls. If networks become congested, handsets installed with a privileged access SIM will stand a much higher likelihood of being able to connect to their network and make calls than other customers. How it works Mobile telephones work on a cell basis. In the United Kingdom, for example, the cells adjacent to the incident are identified and MTPAS is implemented on those cells alone. MTPAS-aware telephones are allowed access to the network and all other users will receive a fast beep (called a fast busy signal). Once the call is connected to the network it is routed like any other. If the user receives a recording that all lines are busy or engaged tone, then either MTPAS users are overloading the available capacity or MTPAS is not being utilised. The MTPAS access class may be indicated on the SIM card or in protected storage on the handset itself, by a set of numbers in the range 0 - 15 giving a total of 16 flag bits in the Access Control Class Elementary File (EFACC) in a USIM. It is not hierarchical so it can allow level 1 access while disallowing level 6 access. If the 16-bit control word is, 1010-0000-0011-1111 only phones with the MTPAS access level of 1, 3, 11, 12, 13, 14, 15 & 16 will accept requests for placing a call. The cell broadcasts the Access Control Classes it allows (or bars) in a System Information Block (SIB) message. It is important to note that the decision whether to permit a call is not made by the cellular network but by the handset itself. In Britain, ordinary cellphone users have numbers in the range 0 - 9. Higher priority