Cameron and Sarkozy sign treaties between UK and France.
Following the events of the 1950s and Egypt's forced nationalisation of the Suez Canal, the United States and United Kingdom continued to drift in their approach to international relations. The two countries had been some of the closest of allies during World War II, but events following the war made clear the difference between an globally ascendant republic and a fading colonial empire with regards to foreign policy. Some elements were not directly the fault of the governments - the revelation of Fuchs, at the heart of the British nuclear weapons programme, as handing over secrets to the Soviets drove a wedge of suspicion between the US and UK and can hardly be attributed to government policy, but it seems that distrust on both sides would fuel further distrust. This, however, then spurred further consequences such as the restricting of nuclear data from being received by United Kingdom from the United States, further frustrating British efforts to remain close to the US.
Coupled on to this in 1956 was the Suez Affair. The nationalisation of the Suez Canal by Egypt was regarded by the British as a deceitful abrogation of earlier British-Egyptian agreements, whilst in Egypt it was viewed as an exercise of domestic sovereignty over it's territory. Early efforts went in to a tripartite effort between the UK, France and Israel to prevent Egypt from striking Israel and also put the canal in to international hands. Those views were rapidly struck down after Macmillian, then Chancellor, met with Eisenhower informally, only to be told that the US would be outraged if Britain militarily intervened and would be a step backwards with regards to keeping Egypt out of the Soviet orbit. Although the level of American involvement in the British economy meant that Eden could hardly ignore the American position on the whole affair, it laid on yet another perceived blow on Britain by the United States, and this was rapidly followed by a repeated refusal from the US Navy this time to share nuclear propulsion technology (*1). In hindsight, this would turn out to be the straw which broke the camel's back of the post-war US-UK relationship. Subsequently, British involvement was only to allow the quiet use of British airfields in Cyprus by France. The Suez Affair provided Britain with a significant push away from efforts to maintain a close relationship with the United States, fearful of an invasion of Western Europe by the Soviets and a seeming American uncertainty over whether to help the Europeans with the weapons to defend themselves. Enquiries by the Americans after the Soviet Sputnik launch in 1957 as to some increased collaboration again were seen in the British Government as proof that the Americans would only act when in their own interest rather than acting collaboratively.
Following Suez, the United Kingdom and France global viewpoints rapidly converged, and began what was inevitably at the time a marriage of convenience - but one which has stuck and grown since. Joint nuclear research officially began formally in 1961, but an informal set of Anglo-French meeting of nuclear scientists had already existed for a few years, separate from the team which worked with the Americans, to whom the French team would sometimes seek validation or confirmation from - a nuclear powered game of twenty questions - to guide their research. Despite the fact this had sunk the initial efforts in to the separate European "Euratom" treaty progress (*2), overall UK-European relations didn't particularly suffer - most likely due to the UK's initial interference with the origins of the Common Market. After the French detonated a test explosion in Algeria in 1959, demonstrating the Anglo-French independent progress, a fully unified nuclear research team started and was formalised in 1961, with a now fully-fledged nuclear weapons effort, and later resulting in a fairly common nuclear missile and launch system. This nuclear sharing and military research, and increasingly aligned foreign policy (despite France being part of the Common Market and the United Kingdom not) has served as the bedrock for the Anglo-French alliance. Both nations elected to not participate, at least directly, in the Vietnam War - despite Vietnam being a former French colony, and worked vociferously to keep the Suez Canal open for traffic despite the continuous fighting in the Middle East. Attempts by the United States administration to improve it's relationship with the United Kingdom kept being undermined by other events; for example, the early 1960s saw the US Civil Aeronautics Boards decline to provide financing for US airlines seeking to purchase UK jetliners, unlike the rival US jetliners (*3).
1964 saw initial efforts in to a Channel Tunnel linking the United Kingdom and France, and this was later followed by a 1968 treaty to build the so-called Chunnel along with a new high speed rail system on either side of it to link London to Paris. Given that the end solution - an end-to-end high speed link - would only realistically work if both sides kept up their side of the bargain, steep cancellation penalties made sure neither side got cold feet, although the British Government, wary about British Rail's financial competence, assigned their share of the work in to a separate rail subsidiary, "Eurostar", from which the later European rail operator would inherit it's name. Construction started on the primary rail tunnel in 1970, opening in 1977, although the high speed rail route in to London (Broad Street) and Paris (Gare du Nord) did not open until three years later in 1980. The rail crossing of the River Thames on the British leg of the route was combined with the new Thames crossing and motorway between Rochester and Brentwood, in an effort to relieve the Dartford Tunnels, although funding issues led to the delay of the road parts by approximately 10 years and potential penalties guaranteeing the rail segments. This axis would form the original basis of the wider European Eurostar network, and continues to be the most profitable segment today due to the amount of public, governmental, research and enterprise travellers between the two capitals. However, the rail project sucked so much capital from both sides, there were plenty of projects not pursued; the supersonic airliner (*4) planned between British and French airliner manufacturers is the most famous example to be dropped which continues to be the focus of "What if..." speculations and stories on minitel (*5) message boards.
The cancellation of the supersonic airliner did, however, spur the creation of "Airbus", an economic partnership of Hawker Siddeley, Breguet and Nord Aviation (*6). This partnership was created to develop a European designed and manufactured airliner, and despite significant political challenges along the way due to the cost - eventually circumvented with the addition of the Germans, managed to start a fully-fledged airliner programme. Standardising on English as a working language - often attributed to the strong US position in the market, the project elected for metric measurements and instrumentation in the face of existing French standards and British efforts to convert to the metric system. This is often quoted as a major reason why European airline systems are today all in metric units, which was later also adopted almost the entirety of Australasia, Asia and Africa (*7). The programme delivered the A300 prototype on it's maiden flight in 1972 from Paris to London, and turned out to be the first of a few Anglo-French joint efforts in aviation.
By the 1970s, the United Kingdom and France (and by extension the Common Market) were growing closer. It was clear that the Commonwealth was no longer the prime trade partner for the United Kingdom; trade had collapsed with the Commonwealth, as many newly independent nations formed their own trade relationships and found more profitable international trade elsewhere. Some right-wing politicians saw this as an ungrateful Commonwealth turning it's back on the mother country, but in reality most could see that the United Kingdom of the 1970s was a far cry from that of the 1800s - it had almost bankrupted itself during two incredibly expensive world wars. Rapidly growing trade with the Common Market was an increasingly reality, and a tight relationship with France, led to the United Kingdom placing it's application for membership of the Common Market on the table in 1978 and rapidly negotiating it's entry alongside the Republic of Ireland, Spain, Portugal and Greece. Negotiations concluded rapidly for the United Kingdom, given it's existing EFTA membership, closely aligned trade with the Europeans and close relationship with France, which allowed the United Kingdom (along with the Republic of Ireland) to hop to the front of the queue - not the least bit aided by the fact the United Kingdom would help balance the impact of Spain and Portugal joining the bloc.
Today, the United Kingdom continued to hold a special relationship with France, built up over the decades - an entente fratenale, instead of cordiale as it once was. Whilst the French-German axis in Europe may be the economic engine of the bloc, London holds the coin, and much of the important global grand-standing for Europe is done by the United Kingdom and France as per two of few nuclear armed nations, United Nations security council permanent members, as well as both with highly capable militaries. Both are (now) traditionally the first foreign trip for a new leader (*8), both countries usually learn each other's language as a first foreign language, and both now share a number of multinational corporations operating in both nations - one of the most publicly obvious being in supermarket shopping, with Carrefour present in many areas of the UK, and the reverse seeing Tesco in many areas of France (*9).
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(*1) From Wikipedia: ...despite Rear Admiral Hyman Rickover, in charge of the American naval nuclear power programme, being set against any transfer of technology; indeed, Rickover prevented Mountbatten inspecting USS
Nautilus. It was not until a visit to Britain in 1956 that Rickover changed his mind and withdrew his objections.
In this TL, that visit to the UK never happens as a consequence of the PoD.
(*2) Butterflying away Euratom, with UK-French efforts largely replacing it.
(*3) This largely happened OTL, but was waved away. It's easy to wave things away when you're good friends, but when you're not on such friendly terms such events appear like a slap in the face.
(*4) No Concorde here, due to cost.
(*5) Cough, minitel, cough cough. What I'm calling the European internet it evolves in to.
(*6) The original Airbus attempts go ahead as UK-French co-operation without the British pulling out.
(*7) I might rewrite this based on feedback if needed, but as far as I can tell, the aviation market uses imperial measurements due to the widespread use of American planes in the infancy of the aviation market. The introduction of this early Airbus, based on UK-French co-operation - with the French already metric, and the UK at this point going metric, might swing much of the market. As far as I can tell, the Soviet Union and China at least used to use metric aviation measurements, so I figured that with the UK-French attempt, the Soviet Union, China and their exports of Airbus planes, it might swing the market in Europe, Africa, Asia, Australasia to metric aviation. If anyone can dig up more detailed information which would invalidate this, please let me know, but that's as far as I could get.
(*8) As far as I can tell, a trip to Paris is high up on the early trips for a new PM anyway.
(*9) Both Carrefour and Tesco did operate in each other's territories in OTL, it just didn't last long....unlike here. I remember shopping at Tesco in France many many years ago.
And also.....no space discussion yet. It's there, it's just not done yet, and likely a chapter unto itself.
PS: Just because Cameron and Sarkozy are in the picture, doesn't necessarily mean they both end up as heads of government; the could both be foreign ministers, relevant defence ministers, something else. Not got anywhere near that far forward yet in writing.
