The four recently elected Catalan MPs and one Senator who are on trial on charges of rebellion have been banned from sitting in the Spanish parliament after winning seats in April's general election.
The five took up their posts last week after a court allowed them to be escorted out of prison for the day. They are currently part of the large trial judging the role of separatist leaders in the illegal declaration of independence in 2017. While the law doesn't stop them being in parliament while still on trial, parliament is entitled to tell them not to attend.
These MPs now have to decide whether to keep the seats, meaning their votes cannot be counted in the upcoming vote on next prime minister, or give them up to others lower down their parties' electoral lists.
Oriol Junqueras, leader of the left-wing of the ERC party is expected to give in his seat and pass it to the next person on the electoral list. Jun queras also won a MEP seat in last Sunday's Euro elections. Jordi Sànchez, Jordi Turull and Josep Rull, three of the MPs of the Junts Per Catalunya party are expected to keep their seats in Congreso.
Raül Romeva of the ERC has a seat in the separate Senate where votes are less crucial.
In Congreso, the absence of any separatist MPs may make it easier for acting PM, Pedro Sánchez, to secure a majority of MPs' support without having to rely on pro-Catalan independence parties.
The king is expected to formally meet with party leaders from next week as the process to choose a new PM begins following the 28 April vote. The decision has been delayed while politicians fought last Sunday's regional, European and municipal elections.