Recent headlines about the Home Secretary have prompted another discussion about the ministerial code, in particular about who should decide if it has been broken and what should happen if it is.

A new version of the ministerial code is produced by each incoming Prime Minister, setting out expectations of conduct of their ministers. I was subject to the terms of two (very similar) versions issued by David Cameron and Theresa May when I was a minister.

As things stand, any potential breach of the code is for the prime minister to determine, assisted if he chooses to be by an independent adviser.

That independent adviser can only investigate a potential breach if the prime minister asks them to do so.

I have recently finished my three-year term as a member of the Committee on Standards in Public Life, which recommended during that term that the role of the independent adviser should change, and I still hold to that view.

I think that the independent adviser and his successors should be able to initiate their own investigations into alleged breaches of the ministerial code if they believe it to be appropriate to do so and then be able to determine whether a breach has occurred.

There would be several advantages to that approach.

It would mean that busy prime ministers would not be spending valuable time investigating the behaviour of their ministers and, crucially, assessments of that behaviour would be made at arm's length from the prime minister and those assessments would consequently be likely to have more credibility with the public.

The question then arises of sanctions when a breach of the code is established.

My view, and that of the Committee on Standards in Public Life, is that this should be a matter for the prime minister.

Prime ministers must determine the fate of the ministers they appoint in the government for which they are ultimately responsible, because they are elected and advisers are not.

Incidentally, another of the committee's recommendations (which was accepted) was that the prime minister should not be restricted to requiring a minister's resignation for any and all breaches of the ministerial code, as was previously the case, but rather should have a range of sanctions available.

All breaches of the ministerial code are not of equal seriousness and not all merit departure from government.

Previous prime ministers have tied themselves in knots to avoid finding a breach of the code in the first place where they did not believe the end of a ministerial career would have been warranted if they had.

This was therefore a sensible change to make, but these recommendations go together and I am convinced that a better and more defensible approach to the ministerial code would result from a bigger role for the independent adviser, in the context of maintaining high standards of ministerial behaviour in which we all have an interest.