Last February, a non-binding motion was submitted by political party PSOE calling on the Spanish government to reconsider joining the unitary patent and Unified Patent Court. Available here.
The motion, approved on March 7th, 2017 by the Industries Committee of the Spanish Parliament (‘Congreso de los Diputados’), highlights the drawbacks of staying out of the project with regard to competitiveness and innovation. Additionally, it suggests requesting that, after the UK exits from the EU, the London seat of the UPC central division is relocated to Spanish territory.
This initiative is not binding on the government, so it only shows a position of some political parties on the issue. At the moment no agenda is known for the possible incorporation of Spain into the system of the unitary patent or potential Spanish ratification of the UPC.