A telecommunications network policy enforcing point (200; 2000) operable to route IP datagrams in a two-way communication between a first endpoint in a telecommunications network and a second endpoint in the telecommunications network and operable to compress, in accordance with a data compression policy, IP datagrams of a response transmitted by the second endpoint to the first endpoint, each IP datagram comprising a sequence of bytes of data and a header defining a sequence number of the first byte of data in the IP datagram, the response being of a layer 7 protocol that supports compression, wherein the layer level is understood in the sense of the Open Systems Interconnection, OSI, Reference Model, the telecommunications network policy enforcing point (200; 2000) comprising: a datagram inspection module operable to determine whether IP datagrams sent from the second endpoint and received by the policy enforcing point (200; 2000) are uncompressed but can be compressed in accordance with the data compression policy by inspecting, in at least one of the received IP datagrams, control information of the layer 7 protocol which is located beyond the IP 5 tuple in the IP datagram; a data compression module operable to compress data in at least some of the received IP datagrams in response to the datagram inspection module determining that the received IP datagrams are uncompressed but can be compressed, thereby generating compressed IP datagrams for transmission to the first endpoint; a header modification module operable to modify the headers in the compressed IP datagrams to take into account a reduction in the number of bytes in one or more preceding IP datagrams caused by compression of the data therein by the data compression module so as to ensure a continuity of said sequence numbers between adjacent compressed IP datagrams in the response transmitted by the second endpoint to the first endpoint; and a communication module operable to transmit the compressed IP datagrams to the first endpoint and receive therefrom acknowledgements of receipt of the compressed IP datagrams, wherein the header modification module is further operable to generate, in response to receipt of said acknowledgements by the communication module, acknowledgments of receipt of the corresponding uncompressed IP datagrams for transmission by the communication module to the second endpoint. a datagram inspection module operable to determine whether IP datagrams sent from the second endpoint and received by the policy enforcing point (200; 2000) are uncompressed but can be compressed in accordance with the data compression policy by inspecting, in at least one of the received IP datagrams, control information of the layer 7 protocol which is located beyond the IP 5 tuple in the IP datagram; a data compression module operable to compress data in at least some of the received IP datagrams in response to the datagram inspection module determining that the received IP datagrams are uncompressed but can be compressed, thereby generating compressed IP datagrams for transmission to the first endpoint; a header modification module operable to modify the headers in the compressed IP datagrams to take into account a reduction in the number of bytes in one or more preceding IP datagrams caused by compression of the data therein by the data compression module so as to ensure a continuity of said sequence numbers between adjacent compressed IP datagrams in the response transmitted by the second endpoint to the first endpoint; and a communication module operable to transmit the compressed IP datagrams to the first endpoint and receive therefrom acknowledgements of receipt of the compressed IP datagrams, wherein the header modification module is further operable to generate, in response to receipt of said acknowledgements by the communication module, acknowledgments of receipt of the corresponding uncompressed IP datagrams for transmission by the communication module to the second endpoint.