1. A call handler (GMSC, HLR; 1 ) that is connectable to a mobile communication network ( 3 ) through which calls are routed to and from mobile stations, where said calls contain call destination information, said call handler (GMSC, HLR; 1 ) being arranged to receive calls that are to be routed and being operable to determine routing information for said received calls by interrogating information stored in said call handler (GSMC, HLR; 1 ) that relates to call destination information contained in a call being routed, to apply said routing information to a corresponding call and to pass said calls into said mobile communication network together with said routing information, and said call handler (GMSC, HLR; 1 ) being arranged to store a current value of at least one mobile station condition parameter, said call handler (GMSC, HLR; 1 ) furthermore being connectable to an intelligent network service handler (gsmSSF, gsmSCF; 2 ) and being operable to perform a decision routine that makes a decision if an intelligent network service is to be invoked, said decision routine being executable to check (S 1 ) if one or more intelligent network identifiers are activated in the stored information that relates to a call destination, and if it is decided that an intelligent network service is to be invoked for a call, said call handler (GMSC, HLR; 1 ) being operable to send at least signaling information associated with said one or more intelligent network identifiers to said intelligent network service handler (gsmSSF, gsmSCF; 3 ), characterized in that said decision routine is furthermore executable such that if a call being handled is a call to be routed to a mobile station, and if it is determined that at least one intelligent network identifier is activated in said stored information, a further determination (S 3, S 4 ) is executable, where said further determination comprises comparing (S 3 ) a stored comparison value of a mobile station condition parameter associated with a corresponding condition of the mobile station to which said call being handled is to be routed, with a current value of said mobile station condition parameter of said mobile station, and where said decision regarding the invocation of an intelligent network service depends (S 4 ) on the outcome of said comparison.