Which PoD at any point at or after 1900 would give us a UK that is more 'vibrant' - more economically, politically, socially, culturally dominant in the world? I'm looking for something that would give 2012 a United Kingdom that has more significant force projection militarily, a higher economic output, and no 'decline' into a socialist state as some would call it, after WW2. OTL, the United States had a huge postwar boom that let it become the dominant superpower, but what could help the United Kingdom to share in that boom and not retreat into itself?
I'm not highly familiar with post-war Britain or the interwar period, so any information would be helpful.