[dragonwriter]

> If the UK spends the next 15 years making trouble in the EU, blocking a Brexit agreement

If they don't trigger Article 50, they have exactly the same role in the EU as if they never chose to leave (except that they lose the special concessions that they just got approved which were contingent on a "Remain" result in the referendum, which, AFAICT, is the only actual legal effect of referendum.)

Once they trigger Article 50, they are out in 2 years (barring an agreement to extend the process.) The only purpose of an exit agreement is to provide an alternative to the default exit terms, which would, e.g., leave trade relations between Britain and the EU reverting to WTO rules.

[gonvaled]

I doubt it. They have legally the same rights and obligations, but in practice I do not see the rest of the EU willing to work with the UK representatives. They will get the minimum legally required, and will have to satisfy the maximum of their legal obligations. British representatives will not be very popular in the european institutions now (not that they were very popular to start with)