When the British lost their belief in Christianity, they became victims of the national characteristic of being practical and common sensical.
Because when this characteristic loses ultimate hope and divine context; and reverts to materialist hedonism; then being 'pragmatic' means perceiving oneself as utterly powerless in the face of officialdom, bureaucracy, mass media and corporations and therefore doomed to obedience and conformity to their wishes.
If mortal life is all there is; and if - in this life - you know that (in the end...) you are outnumbered and out-gunned, and therefore you must and will (eventually) conform to the demands of power.
And when you deny any possible reality greater than such conformity, then there is no reason to think; and British people don't think - indeed they are extremely hostile to thinking.
The British are masters of pre-emptive conformity (because, what is the point?...)
By this I mean that there is considerable anger or fear at the prospect of thinking-through moral and spiritual matters to see whether current ideas are coherent, what their motivations might be... There is an aggressive uninterest in establishing what is really going on, where things are going and 'what I really think' about what is going on and where.
I think this is because British people perceive themselves as in a hopeless situation, now and until extinction at death - so any deep thinking can only waste time and energy, and make matters worse; by introducing futile discontent or despair or attracting the malign attention of authority.
Therefore, there is a single-minded and rather irritable strategic pursuit of pleasure and distraction in order not to think.
At root is rooted despair. Nothing really matters, reality is merely-material, and nothing 'I' can do will make any real difference to anything'.
Consequently, the British - who used to be renowned foes of arbitrary authority and totalitarianism; independent and eccentric - are now mostly short-termist, selfish and cowardly deep-conformists - who are living in denial of the resentment-motivated totalitarian society they have willed upon themselves - and who cannot even imagine any better way of thinking, feeling and living.
And, if life really-is as the ubiquitous atheists conceive it, then why not?