There is a reason why civil servants, including senior police officers, are instructed to stay out of politics. The Met's Bob Quick has just found out why. (More here).
Quick's apology should draw a line under the matter and hopefully the investigation can continue.
However one more thought springs to mind.
I remember a school governor once accusing David Cameron of lying about a boy who turned up drunk to a GCSE exam; when Cameron was proved right, we never found out if the governor apologised for the misguided attack.
If people are going to enter the world of politics they ought to take on the politicans rules; which is that if you are wrong you should, at least, apologise as publicly as you made the original statement and retract. I am glad Quick did this, whilst the governor still hides; Quick may yet still come out of this with his reputation intact or even enhanced.