It is thought that pressure measurements taken from the fluid as it is drained may be able to show doctors whether or not the lung will re-expand before patients are committed to either TP or an IPC. In this research we wish to test if these measurements can be used to choose which is the best first treatment option (TP or IPC) for patients with MPE. We have called this 'EDIT management'. Since it is uncertain whether this new approach will work, patients will be randomised to have either standard treatment or EDIT management. We will compare the two groups to assess whether the patients who had EDIT management had to have fewer repeat procedures over the following 3 months.