Aclerk at the Scottish Parliament recently advised Rab Wilson to change the wording of his submission to the Petitions Committee.

He might not want to claim direct responsibility for influencing ministers' decisions, including the setting up of an NHS whistleblowers helpline, the official said, because "it may diminish your credibility in the eyes of the committee".

There is only problem with that: Mr Wilson almost certainly is directly responsible for this, and other significant changes in improving NHS safety in Scotland such as the recently launched strategy for dealing with adverse medical events.

His five-year battle to access learning reports following serious incidents at NHS Ayrshire and Arran saw him using freedom of information rules to demonstrate that more than 50 incidents, many of which resulted in deaths, had been hushed up by the health board.

That campaign led to damning reports on NHS Ayrshire and Arran from both the Scottish Information Commissioner, then Kevin Dunion, who described it as the worst case he had come across in his role and from NHS Healthcare Improvement Scotland.

But one of the lessons the health board learned was that Rab Wilson does not go away easily, and he is continuing his attempts to improve transparency and safety in the NHS.

This week alone, the former psychiatric nurse has submitted his new petition to the Scottish Parliament; called on the Nursing and Midwifery Council to investigate a senior nursing manager over the NHS Ayrshire and Arran case; met with the current Information Commissioner, and he is fighting a public battle with his union Unison who he feels has failed to support him enough.

In his petition, he is calling on the parliament to ban gagging clauses in the NHS, which are commonly used in compromise agreements with departing workers.

These can prevent staff speaking freely about matters that affect patient safety, he says, as well as other issues such as workplace bullying.

His petition calls on the Scottish Parliament to urge the Scottish Government to ban the use of confidentiality, or so-called "gagging", clauses in compromise agreements with NHS staff in Scotland, which may prevent staff speaking freely about matters that affect patient safety and quality of care, as well as employment issues such as workplace bullying.

"Even now, if you look at my case, no individual at NHS Ayrshire and Arran has been held to account. It has been swept under the carpet," he says. He notes that this week it was also announced that no individuals will face action over the serious problems at NHS Staffordshire, in England. "What the hell's going on? Surely someone's responsible," Mr Wilson mutters.

With a lack of accountability and clear failures to learn from errors and accidents, so-called compromise agreements should not be allowed, he argues.

"Of the 678 compromise agreements signed in the NHS, there have been four 'protected disclosures' by whistleblowers," he says.

"Why are people not going public with these stories?"

One might be almost tempted to view Mr Wilson as a zealot, obsessed with hidden harm in the NHS. However he has a point. Further freedom of information requests led to the publication of more than 300 incident reports from health boards across Scotland which had never been previously revealed.

They included cases of patients dying due to equipment failure, delays, drug errors and numerous other avoidable incidents, as well as dozens of near misses.

"A lot of people are not talking and I think they are terrified to speak out because of the gagging orders. They think they will be taken to court and if they got a pay-off, they think the NHS will claw that back," Mr Wilson says.

"It is very threatening. The Scottish Parliament should vote on this, and call for an end to gagging orders."

Mr Wilson is calling on health secretary Alex Neil to lead the attack on compromise agreements. He is also currently asking him to investigate the process of appointments to NHS boards, after being rejected in his application to join NHS Ayrshire and Arran as a non-executive board member.

Challenging the decision to keep him out would be pointless, he reckons, but he says his application was serious. "I feel that I would have been able to contribute greatly and would have been able to use the knowledge I have gleaned of how NHS Ayrshire and Arran operates over the past six years or so of my whistle-blowing odyssey."

The board posts are a sort of elite club, he claims: "You would think I should at least have been interviewed. How do people get on to these boards? It is another stitch-up. We could really do with some people with practical experience in the NHS in the driving seat so that some of these overpaid executive directors are held to account."

While it looks as though he has a battle on every front, Mr Wilson at least has the ear of the current Information Commissioner Rosemary Agnew.

On Wednesday he met with her to formally close his case, and to discuss other possibilities such as better ways in which whistleblowers can be protected and whether nurses, for instance, should receive guidance on how to use freedom of information requests as part of their training.

A spokesman for the Scottish Information Commissioner said: "The commissioner had a very helpful meeting with Mr Wilson at the conclusion of this long and complex FOI case. The aim was to explore any lessons emerging from Mr Wilson's experiences about the operation of FOI in Scotland.

"Issues discussed included the value of good communication between requesters and authorities, and the importance of ensuring that frontline staff are fully aware of their FOI duties and obligations."

Changing the rules is one goal, Mr Wilson explains, but changing attitudes is more vital.

He says: "As a nurse, when I asked questions I was treated immediately as an enemy. That culture needs to change. The NHS should be encouraging people to seek information and happy to give it out."