It is hard to envisage a happy outcome to the course embarked upon by Spanish Prime Minister Mariano Rajoy in response to the situation in Catalonia

By invoking Article 155 of Spain’s constitution to transfer powers back from the region to Madrid he embarked upon a course which looks doomed from the outset.

It is not clear yet what measures this will involve – the article has never been invoked before. But the law gives Mr Rajoy sweeping powers to restore legality if a regional government is deemed to be facing – or have created – a crisis. They could include taking over the local police force, and Catalonia’s finances, or calling an election.

It is not that the process will not work. These are uncharted waters, but it seems likely that Mr Rajoy can dismiss police chiefs and take charge of Catalonia’s Mossos d’Esquadra force, or could dissolve the government of Catalan leader Carles Puigdemont. But any such solutions will do nothing to resolve the situation in a lasting way. Invoking Article 155 will only exacerbate tensions.

While the Catalan devolved government held a referendum in which 90 per cent of voters backed independence, this lacks legitimacy despite the decisive majority.

With only a 43 per cent turnout it is quite possible that opponents of independence stayed at home, precisely because of concerns that participating would legitimise a plebiscite which had been officially suspended by Spain’s Constitutional Court.

Attempts to retrieve devolved powers to bring the Catalan authorities back into line will merely compound the dismal way in which the Spanish government has managed this crisis – from the aggressive and sometimes brutal policing in the run up to the poll to the arrest and jailing on sedition charges of two leading opposition politicians three days ago.

A better solution for all concerned would be to hold a properly constituted official and binding independence referendum. This would be the democratic way forward and as the UK has demonstrated, can be managed in a peaceful and largely respectful climate.

Whatever your view of the outcome, as a democratic exercise the Scottish referendum was hugely successful, with the electorate exploring the issues, while enfranchising 16 and 17 year olds and allowing the public to make a proper choice, while achieving a still remarkable 84.6 per cent turnout.

Were an official poll to be held, issues such as whether an independent Catalonia could gain membership of the EU, or whether such a state could be viable at all can be aired and scrutinised on both sides.

Spain is a mature democracy, and should be behaving like one. Threats and suppression are not the way to demonstrate this. The constitution may say Spain is indivisible, but assertion is not demonstration. If Mr Rajoy has the courage of his convictions, a binding referendum could settle the issue.