MI5 has issued an alert over the threat posed by rogue workers in Britain ’ s nuclear , transport and public services after suicide pilot Andreas Lubitz killed 150 people in the Alps plane crash disaster . And concerns are so great that one security source has warned : ‘ However much physical security you have , if someone is already in there , there ’ s nothing you can do to stop them committing an act of sabotage or terrorism. ’ MI5 is now giving advice on the risk posed by thousands of employees working in sensitive areas – known as ‘ insiders ’ – highlighted by the Germanwings disaster . Warning : MI5 has issued an alert over the threat posed by rogue workers in Britain ’ s nuclear , transport and public services after co-pilot Andreas Lubitz killed 150 people in the Alps plane crash disaster . Co-pilot Andreas Lubitz , who was being treated for depression , was able to override a security system installed on flights following the 9/11 attacks as he flew the aircraft into the ground . Guidance issued by the Centre for the Protection of National Infrastructure ( CPNI ) , a security agency accountable to the director general of MI5 , recommends continuous psychological assessment of key employees , with the highest priority given to workers whose jobs pose the greatest risk to the public . But a BA pilot , who has been with the company for several years and flies regularly around the world , claimed the airline did not carry out mental health checks . The pilot , who did not wish to be named , said : ‘ British Airways is more interested in checking whether I have a hernia than mental health . ‘ There is no testing regarding mental health. ’ A BA spokeswoman refused to discuss details of health checks carried out on pilots . The CPNI has identified a number of motives for employees becoming an insider threat , including theft , revenge , a hunger for notoriety , political or religious ideology and fear or coercion , where external pressure is exerted on a worker . Rescue workers and investigators work near debris at the crash site of the Germanwings Airbus A320 . A CPNI study showed that three-quarters of insider acts were carried out by employees who had no malicious intent when joining the organisation , but whose loyalties changed after recruitment . Disturbingly , it also found that in many circumstances the workers had been in their organisation for some years before going rogue . Some of the more common insider acts include unauthorised disclosure of information – such as in the case of US whistleblower Edward Snowden – process corruption ( where an employee illegitimately alters an internal process for their own ends ) and corporate espionage . The security source said : ‘ Years ago , the emphasis was on external security . Now ‘ ‘ the insider ’ ’ is the growing threat , as seen in the cases of Edward Snowden and Lubitz . ‘ We advise companies to look closely at their personnel . The higher security clearance they gain over their time of employment , the closer they should be monitored . ’
Alert issued over rogue workers in nuclear , transport and public services . MI5 giving advice on risk posed by employees working in sensitive areas . Follows actions of pilot Andreas Lubitz who killed 150 people in the Alps . A BA pilot claims his airline does not carry out mental health checks .