1. A method of executing instruction packets, each packet having a plurality of instructions, in a pipeline comprising at least first and second instruction fetch stages, a pre-decode stage, an instruction dispatch stage, first and second decoding stages, an execution stage and a write-back stage wherein the method comprises: in said first instruction fetch stage determining the number of outstanding instructions still to be issued for execution and for initialising a packet request depending on said determination; in said second instruction fetch stage sending said request to a memory which stores said packets; in said pre-decode stage identifying from a fetched packet which instructions in each packet shall be issued; and in said dispatch stage dispatching the relevant instructions for execution and updating the number of outstanding instructions still to be issued.