I would think the situation with regard to deployable devices in the UK in the mid 50s was similar to that in the US in the late 40s or the USSR in the early 50s.
Well there was a step change in '53 with
Joe 4 which was a Russian 400Kt H-Bomb.
On the other hand, 25 Blue Danubes in Valiants or Vulcans could have made a very considerable mess of Russia.
Yes but...
You're assuming they'd all reach their targets, would not blow up accidentally and that they would actually detonate when they reached their targets.
One Blue Danube would make a considerable mess wherever it blew up either partially or fully.
There's no real evidence that nuclear weapon deployment diminished as a result of Grapple.
Yes that's true I'm trying to understand why so few were produced when the projection for production had been for around 200 by '58 they'd made around 20.
To single out the UK for an inadequate deterrent is unfair.
There is no way on Earth that the UK could ever single handedly match the nuclear production capabilities of either the US or the USSR. The UK needed the US and that was the reason for perusing the nuclear option in the first place. The goal was never to compete independently, the goal was always to seek co-operation from the US that was the whole strategy. Macmillan's 'great prize'