Permanent Under Secretary at the MoD Ursula Brennan said: ‘The assessment of the risk to HMS Westminster would have taken in to account the other capabilities that we had in terms of submarines, aircraft and surveillance and so on and said “in those circumstances, do we think that is a risk worth taking?”.
I'm not saying I'm an expert or have 1st hand experience of life in Whitehall, but the general observation is just that.