There is a blurring of responsibilities in the MoD between DE&S and the DH that causes problems in this area. The MRP tries to make it clear, but it doesn't work all that well in practice. The DH will say that only they can truly control the risk to life, i.e. the individuals exposure, and they would be right. But it is often DE&S, in combination with the supplier, who really (should) understand the equipment and how it contributes to the risk. So in reality, they need to work together.
Excellent.
Now read Wg Cdr Spry thread and the comments on the new definition of Functional Safety. It then becomes obvious why there is blurring and confusion.
A key question is, for EQUIPMENT fitted to an AIRCRAFT, who owns the Equipment Safety Case? And what happens when the Equipment Safety Case is valid for one aircraft, but not for another?
The answer and how to manage the risk has always been well known. But not resourced and no longer taught. To such a degree you now get Wg Cdr Spry's safety organisation getting the definition completely wrong. That means DE&S and RqMs no longer have a policy basis for financial bids to do the job properly.
This failure contributed significantly to the Tornado/Patriot and Sea King ASaC accidents in 2003 and, of course, Nimrod XV230.