"I know that I have made mistakes but I am not a liar."
The words of fallen transport secretary Stephen Byers, speaking at 10 Downing Street last week after resigning from his post, may have plucked on the heartstrings of a few observers. But many more will have noted that Byers was hardly the most dispassionate of people to comment on his own truthfulness.
One might as well have asked David Beckham, rather than his physiotherapist, whether his metatarsal was up to free-kick duties in the World Cup this week.
A similar conflict of interest was at play when two air marshals concluded that gross negligence on the part of RAF pilots was to blame for the crash of Chinook helicopter ZD 576 on the Mull of Kintyre in 1994.
The RAF is surely the last body one should look to for an objective assessment of the root cause of the crash. A finding of possible failure on the part of the helicopter would, after all, suggest that the MoD and the RAF were in the habit of sending British servicemen into the air in machinery that was known to be flawed.
The MoD's own safety specialists had refused to give the helicopter their unqualified approval because of concerns over the engine control software. Boscombe Down wanted the software rewritten, but the MoD disagreed and allowed the Chinook Mk2 into operational service.
In the course of its inquiry, the RAF Board of Inquiry approached Boeing - the company that manufactures the Chinook helicopter - when it needed to carry out a flight simulation to assist its investigation.
It came as no surprise when the Boeing simulation supported the air marshals' finding that the two pilots were grossly negligent - nor was anyone surprised when the MoD and Boeing laid no hint of blame on the helicopter's safety-critical software.
But the Public Accounts Committee and a Select Committee of the House of Lords concluded that software problems could not be ruled out as a possible cause of the crash. Both committees said the RAF Board of Inquiry's verdict of gross negligence was unjustified.
Now it appears that the MoD is planning, if not a flat rejection of the Lords report, a response to the effect that it has no intention of overturning the verdict of gross negligence.
Lord Chalfont, long a campaigner for justice for the pilots of flight ZD 576, has written to the prime minister asking him not to take advice on the verdict of gross negligence from the MoD. The MoD's conflict of interest in this matter is clear for all to see.
The prime minister must either intervene before the secretary of state for defence rejects the Lords' findings or refer the matter of Chinook ZD 576 to an independent third-party organisation that is in a position to make an impartial ruling.
If Tony Blair does not do this, a conflict of interest will be allowed to perpetuate a gross miscarriage of justice.