The NHS and hazardous industries, such as aviation, often use the Swiss cheese model of accident causation, or the “cumulative act effect”.

The model likens human systems to several slices of Swiss cheese stacked together side by side. It was developed by James T Reason, a psychologist and author of Managing the Risks of Organizational Accidents.

People should be encouraged to be responsible for their own actions, but failures should be seen as an opportunity for the collective to learn from mistakes

Holes in the slices of cheese represent the imperfections in safeguards or defences. Reason says that most accidents can be traced to one or more of four levels of failure: equipment; processes; people and the hazard; or an unsafe act itself.

The system as a whole fails when holes in each of the slices align. Reason says this permits “a trajectory of accident opportunity”, so that a hazard passes through a hole in each of the defences, leading to a system failure.

People should be encouraged to be responsible for their own actions, but failures should be seen as an opportunity for the collective to learn from mistakes.

Adverse events should, on the whole, be seen as a systemic failure, not as the fault of an individual.

This works best, however, in a blame-free error reporting culture - something that the hazardous industries have achieved more effectively than the NHS.

Whistleblowing has its place, but the NHS should move on from the stage where this is the default setting. Finding someone to blame will not help your team understand why something went wrong.

If the culture changes to one of accountability, the NHS can better manage patient risk. It is not effective to look for single acts or errors - adverse events usually occur because of a combination of different factors that have been part of the system for years without being changed.

Human beings make mistakes - errors will happen in the best run health systems in the best organisations.

Instead of attempting to sweep failure or imperfections under the carpet - as one NHS trust has recently been accused of doing when a nurse expressed concern over a colleague’s qualifications - managers should address them.

The nurse was allegedly relieved of her management responsibilities and told to drop the case. But if the employee whose credentials were in question had managed to slip through the layers of control and find employment in a position that really necessitated more appropriate training or qualifications, why not openly and honestly find a way to stop that situation occurring in future?

This might mean more stringent checks on potential employees, or better training offered to current staff to keep them up to date.

Medical error can be the result of system flaws, not just character flaws. There will always be holes in the NHS’s layers of Swiss cheese.

But it can work to improve its systems, making those holes smaller and preventing them from aligning so often.