Some estimates put the bill to replace our "independent" nuclear submarine fleet at more than £100 billion. Most countries don't have nuclear weapons, let alone an "independent" nuclear deterrent. Even the Labour party supports Trident's replacement. This is at a time when we complain there are not enough police or people able to analyse people who may be a terrorist threat to the UK.
Why not scrap Trident and spend some of the money on police and anti-terrorism?
No-one in their right mind would press the nuclear button. It would lead to widespread death and destruction. We need things to counter the threats of today.
As for nuclear deterrence, how do most countries manage without such weapons perfectly well? Just a small fraction of the Trident replacement costs would go a very long way.