I was asked to sign off on an R&D tax claim for my team's work. I reviewed it and said no. Was then sent to a meeting with the accountants who explained the claim was based on what the CEO had told them. We went through the details and the agreed with me on most things. I also discovered that we were entitled to claim for things I wouldn't have known about and the CEO discovered that just because the credits were for R&D the legal definition didn't allow for normal development work.

In this instance nothing intentionally illegal was being attempted. However, had the original claim been made it could have been considered fraud. In these sorts of situations I always ensure that the company put me in contact with the professionals that can indemnify both the company and me from any wrong doing. Provided we tell the truth.