The coronal mass ejections causing the most spectacular space weather events are widely believed to be magnetic flux ropes - twisted bundles of magnetic field - that erupt from the Sun. There is an increasing international focus on understanding these events to improve space weather prediction. It is timely for a session bringing together researchers from both UKSP and MIST who focus on diverse aspects of this chain events. The session will focus on fundamental outstanding problems, such as predicting where and when flux ropes will form and erupt on the Sun, how quickly they will reach the Earth, or how they will interact with our magnetosphere.