Method and system for monitoring the integrity of a pressurised tank

This invention relates to checking the integrity of a pressurised tank using pressure measurements obtained during a filling process. A measured pressure profile is compared with a reference pressure profile to determine whether the measured and reference pressure profiles correspond. The integrity of the tank is confirmed if the measured and reference pressure profiles are found to correspond, or otherwise a problem with the integrity of the tank is reported. How the profiles differ may be characterised and used to indicate the type of problem with the integrity of the tank.