By Javier Argomaniz

Barcelona has bled before. Just over 30 years ago, the Catalan capital was struck by the bloodiest attack ever carried out by ETA. Twenty-one people died and another 45 were injured in 1987’s Hipercor supermarket bombing.

This week it was Jihadis bringing death to its most famous street, Las Ramblas, and not Basque separatists. But as Barcelona recovers it is worth bearing this mind: Spain has experienced terrorism before and its people have resilience.

In 2004 nearly 200 people died and 10 times as many were hurt in Europe’s worst jihadist terror incident, the Madrid train bombings usually referred to as 11-M, or March 11 in an echo of New York’s 9/11.

Ever since Spain, along with the rest of the continent, has been on alert. The threat is substantial. This year in Catalonia alone there have been 14 arrests and 10 investigations. Last year there were 69 jihadist terror arrests in Spain, the second highest figure in a decade.

After 11-M, Spain’s varied police forces, including Catalonia’s autonomous Mossos, have shared information after there were suggestions that different organisations had difference pieces of the puzzle ahead of the Madrid atrocities.

Investigators are still putting together the story of this week’s events in Barcelona. But there has been a changing pattern in the nature of terror suspects in Spain. Until 2012 they were mostly foreign-born. But since then there has been an emerging trend for home-grown terrorism. Almost half of them are born in Spain, in a chilling sign of the power of ISIS propaganda.

Barcelona has been one of the hotspots for this radicalisation, simply because, along with Madrid, it is where communities vulnerable to this, including Moroccans, have settled.

But Spain does not seem to have the scale of problem as some other countries. Some 178 people from Spain, many of them from the enclaves of Ceuta and Melilla on the Moroccan coast, are ISIS fighters in Syria or Iraq. The figure is 10 times higher in France.

In Catalonia this week we have seen a vehicle used as a weapon in a trend that has been copied, not just by ISIS in London, Nice and Berlin but by other extremists, including in Charlottesville in America and at Finsbury Mosque in London.

This is a tactic which is hard for the security services to prevent. It does not require training to drive a vehicle into a crowd but it can be deadly and this is a tactic available to terrorist sympathisers that lack the means to carry out more sophisticated attacks

We do not know yet why Las Ramblas was targeted. But we can speculate that this is the kind of busy tourist spot where attackers can expected maximum publicity. Such attacks in the past - in Paris, for example, have hurt tourism as people stay away. We may see that in Barcelona. But the city will bounce back.

Dr Argomaniz lectures at St Andrews on terrorism