I said it was chump change compared to overall government spending, not specific departmental spending. Obviously I know that £3bn is would be a huge sum to some departments. You don't need to be Burnsy2023 to spot the obvious.
And as I said, if people are so concerned about increasing spending in specific departments, we ought first to look at the massive waste and inefficiencies rather than sacrificing our national detterence.
Failing that, I'd sooner scrap foreign aid than Trident.
What exactly do you base this theory on? If Russia nuked us, there is no guarantee that the US or France would respond. Absolutely none. Treaties don't mean squat when the wholesale extermination of your nation is on the table.
And although I don't think Russia would consider a war with the UK today, who knows where we'll be in ten years time. The EU and NATO might collapse by 2020. Then we'd be wishing we had our nuclear detterence to keep us safe, but we scrapped it so someone with terminal cancer can live long enough for us all to get cancer from Russian warheads.