Puigdemont could become regional president from January 30

Catalunya's Parliamentary chairman Roger Torrent, from the pro-independence party Catalunya Left Republicans (ERC), announced the date and time earlier today for the only candidate for regional president to be officially invested in the role.

This came just a few hours after Spanish government deputy president Soraya Sáenz de Santamaría announced her cabinet had started the ball rolling on preventing it.

The right-wing PP government has taken the first steps towards appealing to the Constitutional Court to stop Puigdemont being sworn in.

He is likely to face technical difficulties in any case – thanks to his key role in the disputed independence referendum, Puigdemont faces arrest if he sets foot on Spanish soil again.

Currently in exile in Belgium, he is safe from custody as the European arrest warrant issued after he fled with four of his ex-ministers was annulled.

But regional or national president cannot normally be sworn in 'remotely' – he or she has to be present at the ceremony, which starts with a cross-party debate and then a vote.

Pro-independence parties gained a collective majority in the December 21 regional elections called by the State, which had by then seized control of Catalunya and fired its government en bloc.

For Puigdemont to be invested as regional president, he needs 68 votes in favour to give him an outright majority – and, with Junts per Catalunya (JxCat), ERC and the CUP having 70 seats between them, this appears to be straightforward.

In the unlikely event the first round fails, a second voting must be held within 48 hours and Puigdemont will then only need a simple majority in favour – more 'yes' than 'no' votes – meaning the overall figure will not be affected by any parties or politicians who choose to abstain.

Should this also fail, Catalunya's Parliamentary chairman has two months to reconvene a swearing-in debate and ceremony by proposing a candidate, who may be Puigdemont but could be someone else if he deems fit.

Where a second investiture fails, Catalunya's Parliament will have to call a fresh election immediately, to be held within 54 days.

This extreme has never yet affected Catalunya's regional Parliament, although for the first time in history, Spain's national government had to call a second election in summer 2016 when Mariano Rajoy failed both rounds of two investiture ceremonies.

He narrowly avoided the same fate after the second general election, which could have meant a third being held on Christmas Day, although several parties who were not in favour of his being president decided to vote for him anyway to end Spain's 11-month government-free hiatus and get the annual budget signed off.

In Catalunya, the first regional president was Jordi Pujol, who had to go through to a second investiture round in his first year, 1980 and in 1995, although continued at the head of the regional government until 2003.

Pasqual Maragall took over until 2006 and then José Montilla until 2010, both of whom were voted in immediately.

Artur Mas, Puigdemont's predecessor, also went through to round two in 2010, but stayed in government until 2015 when all the pro-independence parties made a tactical decision to replace him from the following year, a move Mas reluctantly agreed with.