Secularism need not stifle economic growth, as witness the case of China, whose economy is outperforming both those of Europe and America - and yet (according to that Win-Gallup poll) whose population is at least 60% atheist.
Not, too, that the percentage of China's population that identified themselves as atheist (60%) far exceeds that of Britain's (13%). That would strongly suggest that the British population has retained a belief in God, but has had a complete fill of religion (I wonder why!)
Bill.