There is a fifth thing that I only say in smaller rooms.

It is that the reason this worked is that Charlotte Sinclair happened to walk into a building where the person at the desk had done four years in a school liaison job and had been to a training in 2011.

If she had walked in on a different shift, to a different officer, on a busier day — I do not know.

I would like to say it would have gone the same way.

I have twenty-nine years and I am not going to say that.

That is not a comfortable thing to put in writing and it is the truest sentence in this account.