Switzerland has never been a member of the EU, but was a founding member of EFTA (the European Free Trade Area) and as a result of over 100 bilateral trade agreements (UK Government, please take note!) has access to the single market with some notable exceptions (e.g. financial services). As a condition of this relationship, it contributes to the EU budget and must abide by EU trade legislation (but, of course, has no hand in shaping it). Some ignorant politicians in the UK suggested that the UK should follow the Swiss model in a post-Brexit world – they are ignorant because they failed to take note of a Swiss referendum in 2014 which narrowly (50.3%) decided to place a cap on migration from the EU. The Swiss constitution requires that this binding decision be enacted within 3 years – by next March. (The UK referendum is advisory only and has no legal force).
Initial reaction from Brussels would have been privately apoplectic, but it was limited to terminating Swiss participation in the Erasmus student exchange scheme and freezing Swiss involvement in pan-European scientific research projects in the pipeline at the time (UK scientists may still participate in planned research, but since a European consortium is needed, they have been frozen out by their potential partners within the science community for fear of damning the project to rejection when it goes to the EU).
The Swiss authorities are keen to retain unfettered access to the single market since the EU is its largest export market, but those who called for the initial referendum are just as keen to see it passed into law. It seems crystal clear that the EC (and probably the wider EU nation states (with maybe one exception)) will not allow Swiss access to the single market if it seeks to restrict the freedom of movement of EU citizens to live and work in Switzerland. This leaves the Swiss government between a rock and a hard place and it probably means that the UK government will not be triggering Article 50 until they see the outcome of the “Chexit” crisis.
The reality of the European dream is that pretty much all of the bloc’s 28 nation states are split 50:50 (±5%) on its merits and that very few of the electorate (or, seemingly, politicians) understand the EU, its aims, advantages and powers. Should the EU address this sensibly and urgently then perhaps Switzerland and the UK will be dissuaded from heading for the exit.