Tuc, the CPS prosecute as a result of the findings of the Police investigation. The HSE have the power to initiate prosecutions as a result of their investigation. Not many Agencies have this power, the only other which comes to mind is the CAA. In general the HSE only act when they find evidence of a gross breach of the duties in the HASAWA. This is a pretty tough test and such prosecutions aren't common. The HSE must have determined that MBA did something in breach of the duty or, perhaps more likely, failed to do something (or even can't prove that they did something).
EAP