ERC, the Catalan nationalist coalition, announced today in Congress that “within weeks” they would be tabling the proposed Catalan Independence Referendum Bill, together with a timetable, for the approval of Congress.
The PP has stated before that they will reject any attempt to table such legislation and will not permit a referendum, so this is going to cause a fuss.
Anyway, the question will be “more or less”: Are you in favour of the independence of Catalonia? Yes or No”, along with a timetable for the referendum.

Rajoy has replied, saying that the future is in union, not separation, and warning of the dangers of being a single little state outside of Spain and the EU.