Quite right. I remember Ben Goldacre's book Bad Science documenting a few examples. I hope these are the same examples raised in the letter, because otherwise a lot of miscarriage of justice has happened in the UK.
What I remember from the book is entirely innocent people jailed because the wrong statistical question was asked. IIRC along the lines of two deaths, and the question asked was what is the chance of this happening? As opposed to, assuming the first death, what is the chance of the second? As opposed to, assuming two deaths, what is the chance of bad luck versus malice.
(I am not commenting on the Letby case per se. AIUI there is an appeal pending and UK law can be rather strict. Simply, we should not respond to possible horrible events by convicting other people who are innocent of statistical flukes, or misrepresented statistics.)