A method of transmitting blocks of data from a transmitter entity to a receiver entity in a wireless telecommunications system in which blocks of data are transmitted a plurality of times in a corresponding plurality of time periods using transmission resources in each time period selected from among available transmission resources for transmitting the blocks of data; wherein the method comprises: determining a first block of data has become available for transmission from the transmitter entity to the receiver entity; determining an initial selection of transmission resources for a plurality of transmissions of the first block of data in a corresponding plurality of time periods, wherein the plurality of transmissions for the first block of data comprise a first transmission and one or more repeat transmissions; beginning transmission of the first block of data using the initial selection of transmission resources; determining a second block of data has become available for transmission from the transmitter entity to the receiver entity before the plurality of transmissions for the first block of data are complete; modifying the initial selection of transmission resources for the time periods remaining for repeat transmissions of the first block of data to reduce the amount of transmission resources selected for repeat transmissions of the first block of data that have not yet been made, thereby increasing the amount of transmission resources remaining available for transmitting the second block of data during these remaining time periods for repeat transmissions of the first block of data; determining a selection of transmission resources for at least one transmission of the second block of data in a corresponding at least one time period which overlaps with the time periods remaining for repeat transmissions of the first block of data according to the initial selection of transmission resources for transmitting the first block of data; and transmitting the second block of data using the selection of transmission resources for the second block of data and transmitting remaining repeat transmissions for the first block of data in accordance with the modified selection of transmission resources for the first block of data. determining a first block of data has become available for transmission from the transmitter entity to the receiver entity; determining an initial selection of transmission resources for a plurality of transmissions of the first block of data in a corresponding plurality of time periods, wherein the plurality of transmissions for the first block of data comprise a first transmission and one or more repeat transmissions; beginning transmission of the first block of data using the initial selection of transmission resources; determining a second block of data has become available for transmission from the transmitter entity to the receiver entity before the plurality of transmissions for the first block of data are complete; modifying the initial selection of transmission resources for the time periods remaining for repeat transmissions of the first block of data to reduce the amount of transmission resources selected for repeat transmissions of the first block of data that have not yet been made, thereby increasing the amount of transmission resources remaining available for transmitting the second block of data during these remaining time periods for repeat transmissions of the first block of data; determining a selection of transmission resources for at least one transmission of the second block of data in a corresponding at least one time period which overlaps with the time periods remaining for repeat transmissions of the first block of data according to the initial selection of transmission resources for transmitting the first block of data; and transmitting the second block of data using the selection of transmission resources for the second block of data and transmitting remaining repeat transmissions for the first block of data in accordance with the modified selection of transmission resources for the first block of data.