The British American Security Information Council (BASIC) has an interesting take on this. It's worth a read.
The Implications Of The Trident Test Failure | British American Security Information Council
Amongst other things, the author, Paul Ingram, talks about
.... so much irrational fear within Downing Street that puncturing that collective bubble of confidence in the Trident system could lead to mass defections in the forthcoming vote to renew it. They must have known
the long term damage this would cause to their reputation ..... It certainly tarnishes the image of a Prime Minister attempting to develop a reputation for straight-talking and openness. Theresa May’s
refusal to deny or to clarify the issue yesterday has only made matters worse .... The government could have turned it into an asset by demonstrating its openness. As it is, this episode leaves anyone with an open mind feeling manipulated, and must surely magnify existing cynicism.
airsound