Tumour cells metastasise via a series of discrete biological processes that allow cells to disseminate from the primary tumour, move and colonise distant sites within the body. Our research focuses on understanding the molecular mechanisms whereby tumour cells can metastasise. We are using mouse models of metastatic cancer carrying fluorescent reporters that allow us to follow the metastatic process in real time using whole body imaging, while high resolution intravital microscopy allows us to follow the behaviour of single cells in the tumour micro-environment. This provides a unique way to study these processes and allows us to monitor drug efficacy and mechanism of action of new molecularly targeted agents that are currently in clinical development. We hope that this approach will lead to the development of more effective treatment strategies.