The "special relationship" between the UK and USA is a relatively recent thing. Both countries went to war against each other twice shortly after US independance (I think) and I remember reading an article about how tensions had been rising between the UK and USA between the world wars - the inference being that - had Germany not kicked off again - there was a real possibility of a world-war between the UK and USA. Not that surprising when you look at it: two rival empires competing for dominance, influence and resources.
In the imediate aftermath of WWI many assumed the UK and US would square up and fight it out. However before the rise of US naval power in the 20th centuary there was a tacit agreement of sorts that the UK would look after US interests, from a naval stand point through the late 18th centuary allowing America to remain largely a western hemesphere power and still be able to trade beyond there. There were obvious flash points and tensions but Londons refusal to back the South when it could have entered the war and pretty much broken US power for ever is worth noting.
After WWI the Anglophnic powers decided to negotiate a world order rather than do what the UK had done to Spain, Holland, France, Germany and every other challanger at sea, destroy there sea power. They produced the Washington Naval treaty to set in place an international strategic arms limitations treaty and to effectively devide up the world into spheres of influence.
Post war the special relationship was very real, but like every international relationship far from harmonious. They often cosponsored coups (Iran notibly) and worked hand in glove in many key areas, accessing intelligence at levels that are normaly far beyond the pale for allies (allegedly). UK airpower and sea power was all but an extention of the US armed services in defending the GIUK gap.
Those who argue against the special relationship perhaps fail to appreciate the Falklands war where a US ally dicatator was hung out dry in front of the entire of South America by the US in order to back the UK. It was not a popular move in the eyes of many western hemesphere types in the US and did a certain amount of damage to US credibility.
The UK co-owns an ENLIT satalite with the US that it get (I think) 1/3rd access time to.
Who else has ever sold an entire ICBM to another country? Not IRBM or other rocket artillary but a full blown submarine based missile system?
Doesnt mean they wont fuck each over from time to time.