A vector data transfer instruction is provided for triggering a data transfer between storage locations corresponding to a contiguous block of addresses and multiple data elements of at least one vector register. The instruction specifies a start address of the contiguous block using a base register and an immediate offset value specifies as a multiple of the size of the contiguous block of addresses. This is useful for loop unrolling which can help to improve performance of vectorised code by combining multiple iterations of a loop into a single iteration of an unrolled loop, to reduce the loop control overhead.