The secrecy and subterfuge behind the Iraq war links Spain to Islamist terror. Jose Maria Aznar, the Prime Minister at the time, and his government misled the country by claiming that a devastating massacre in Madrid, a direct retaliation for the invasion, was the work of Basque separatists rather than al-Qaeda.

Mr Aznar had backed George W Bush and Tony Blair in the conflict which is now recognised as a catalyst for the upsurge in jihad which continues to this day. The coordinated attack on commuter trains at the Spanish capital in March 2004, killing 192 people and wounding 1,800, remains the deadliest terrorist attack on Europe this century and was among the first of the murderous backlash.

Spain had escaped the worst of the Islamist terror attacks suffered by other European states since then. Some government ministers had claimed that this was due to the experience in confronting the Basque militants of ETA over decades and also because the country’s Muslim population was relatively assimilated.

A similar conceit had existed, to an extent, in the UK with its experience with the IRA and a similar view about the Muslim population before this was blown away by the 7/7 bombings and the atrocities which followed.

Security officials had been warning for a while that Spain, too, would be an arena for global jihad. The Iberian peninsula, which was under Moorish rule from the early 8th to the end of the 15th century, features regularly in Isis and al-Qaeda messages as Muslim land stolen by Christians which should be a primary target for retribution. One recent Isis exhortation was for assaults on tourist venues using guns, bombs and trucks.

A number of planned attacks had been averted, including one three months ago by two men of Moroccan origin who were allegedly planning to use vehicles and explosives in Madrid. One of them had sought to get a licence for a specific type of truck, the same as the one used to murder 86 people in Nice on Bastille Day last year. Another suspect detained five months earlier had also said he wanted to emulate what happened at Nice.

​Europol figures show that Spain had the second highest number of Islamist terrorist arrests, with 187, in 2015. France was top with 424. However, the Muslim community make up 2.1 per cent of the population in Spain compared to 7.5 per cent in France.

As in other countries, there has been increasing evidence in Spain that prisons had become recruiting ground for jihad. According to reports in Spain some of those who plotted the Barcelona and Cambrils attacks had previous criminal convictions.

A study by academics from the University of Granada and officials from the Union of Prisons found that: “The activities of jihadist recruiters are not curtailed once they are arrested and deprived of their liberties but can be continued within penitentiary institutions. Radical extremists are able to carry out various activities within prison walls, indoctrinate, generate group identity, legitimise terrorism… Activities that may be considered favourable for Islamist radicalism and recruitment.”

There are now additional pressures on public safety. Around 170 Spanish Muslims have gone to fight in Syria. This is a lower number than some other European states, but the whereabouts of most of them are unknown. In addition the security agencies say they are monitoring 1,100 people with extremist views. The country is also receiving large numbers of refugees from North Africa with 9,000 arriving in the last eight months, three times as many as last year. Although the vast majority are genuinely seeking refugee status there are indications, say security officials, that Isis, as it loses its bases in Libya, is trying to infiltrate fighters.

Barcelona Attack Show all 30 1 /30 Barcelona Attack Barcelona Attack Police officers patrol on Las Ramblas following yesterday's terrorist attack, on August 18, 2017 in Barcelona, Spain. Thirteen people were killed and dozens injured when a van hit crowds in the Las Ramblas area of Barcelona on Thursday. Spanish police have also killed five suspected terrorists in the town of Cambrils to stop a second terrorist attack Getty Images Barcelona Attack Tourists and locals walk along Las Ramblas following yesterday's terrorist attack, on August 18, 2017 in Barcelona, Spain. Thirteen people were killed and dozens injured when a van hit crowds in the Las Ramblas area of Barcelona on Thursday. Spanish police have also killed five suspected terrorists in the town of Cambrils to stop a second terrorist attack. Getty Images Barcelona Attack Police officers patrol on Las Ramblas following yesterday's terrorist attack, on August 18, 2017 in Barcelona, Spain. Thirteen people were killed and dozens injured when a van hit crowds in the Las Ramblas area of Barcelona on Thursday. Spanish police have also killed five suspected terrorists in the town of Cambrils to stop a second terrorist attack. Getty Images Barcelona Attack People leave a fastfood with hands up as asked by policemen after a van ploughed into the crowd, killing two persons and injuring several others on the Rambla in Barcelona on August 17, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least two people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack" and a police source said one suspect had left the scene and was "holed up in a bar". The police source said they were hunting for a total of two suspects AFP/Getty Barcelona Attack Police officers tell members of the public to leave the scene in a street in Barcelona, Spain, Thursday, Aug. 17, 2017. Police in the northern Spanish city of Barcelona say a white van has jumped the sidewalk in the city's historic Las Ramblas district, injuring several people. AP Barcelona Attack Injured people react after a van crashed into pedestrians in Las Ramblas, downtown Barcelona, Spain, 17 August 2017. According to initial reports a van crashed into a crowd in Barcelona's famous Placa Catalunya square at Las Ramblas area injuring several. Local media report the van driver ran away, metro and train stations were closed. The number of people injured and the reasons behind the incident are not yet known. Official sources have not confirmed that the incident is a terrorist attack. EPA Barcelona Attack People flee the scene in Barcelona, Spain, Thursday, Aug. 17, 2017 after a white van jumped the sidewalk in the historic Las Ramblas district, crashing into a summer crowd of residents and tourists and injuring several people, police said. (AP Photo/Giannis Papanikos) AP Barcelona Attack People are pictured inside Systemaction, a locked down store after a van crashed into crowds on Las Ramblas in Barcelona, Spain, August 17, 2017. Courtesy Abbie Yermus/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. REUTERS Barcelona Attack People take shelter inside a shop in Barcelona, Spain, Thursday, Aug. 17, 2017. A white van jumped up onto a sidewalk and sped down a pedestrian zone Thursday in Barcelona's historic Las Ramblas district, swerving from side to side as it plowed into tourists and residents. Police said 13 people were killed and more than 50 wounded in what they called a terror attack. (AP Photo/Manu Fernandez) AP Barcelona Attack People move from the scene after a van crashed into pedestrians near the Las Ramblas avenue Reuters Barcelona Attack A policeman stands next to an ambulance after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona AFP/Getty Images Barcelona Attack People are evacuated from a street after a van crashed into pedestrians near the Las Ramblas avenue in central Barcelona, Spain, August 17, 2017. REUTERS/Stringer NO RESALES. NO ARCHIVE. Reuters Barcelona Attack Firefighters stands outside an evacuated mall after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona AFP/Getty Images Barcelona Attack Policemen stand next to vehicles in a cordoned off area after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona AFP/Getty Images Barcelona Attack Plain-clothes policemen phone as they walk past police cars in a cordoned off area after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona AFP/Getty Images Barcelona Attack A policemen and a medical staff member stand past police cars and an ambulance in a cordoned off area after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona AFP/Getty Images Barcelona Attack A person is stretched out of a mall by medical staff members in a cordoned off area after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona on August 17, 2017. Police in Barcelona said they were dealing with a "terrorist attack" after a vehicle ploughed into a crowd of pedestrians on the city's famous Las Ramblas boulevard on August 17, 2017. Police were clearing the area after the incident, which has left a number of people injured. AFP/Getty Images Barcelona Attack Children, some in tears, are escorted down a road in Barcelona, Spain, Thursday, Aug. 17, 2017. Police in Barcelona say a white van has mounted a sidewalk, struck several people in the city's Las Ramblas district. AP Barcelona Attack Mossos d'Esquadra Police officers and emergency service workers move an injured man, after a van crashes into pedestrians in Las Ramblas, downtown Barcelona, Spain, 17 August 2017. According to initial reports a van crashed into a crowd in Barcelona's famous Placa Catalunya square at Las Ramblas area injuring several. Local media report the van driver ran away, metro and train stations were closed. The number of people injured and the reasons behind the incident are not yet known. Official sources have not confirmed that the incident is a terrorist attack. EPA Barcelona Attack Mossos d'Esquadra Police officers attend injured people after a van crashed into pedestrians in Las Ramblas, downtown Barcelona, Spain, 17 August 2017. According to initial reports a van crashed into a crowd in Barcelona's famous Placa Catalunya square at Las Ramblas area injuring several. Local media report the van driver ran away, metro and train stations were closed. The number of people injured and the reasons behind the incident are not yet known. Official sources have not confirmed that the incident is a terrorist attack. EPA Barcelona Attack Injured people react after a van crashed into pedestrians in Las Ramblas, downtown Barcelona, Spain, 17 August 2017. According to initial reports a van crashed into a crowd in Barcelona's famous Placa Catalunya square at Las Ramblas area injuring several. Local media report the van driver ran away, metro and train stations were closed. The number of people injured and the reasons behind the incident are not yet known. Official sources have not confirmed that the incident is a terrorist attack. EPA Barcelona Attack A police officer cordon off a street in Barcelona, Spain, Thursday, Aug. 17, 2017. Police in the northern Spanish city of Barcelona say a white van has jumped the sidewalk in the city's historic Las Ramblas district, injuring several people. AP Barcelona Attack TOPSHOT - Policemen check the area after towing away the van which ploughed into the crowd, killing at least 13 people and injuring around 100 others on the Rambla in Barcelona, on August 18, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". The driver of a van that mowed into a packed street in Barcelona is still on the run, Spanish police said. / AFP PHOTO / Josep LAGOJOSEP LAGO/AFP/Getty Images AFP/Getty Images Barcelona Attack TOPSHOT - Armed policemen stand in a cordoned off area after a van ploughed into the crowd, injuring several persons on the Rambla in Barcelona on August 17, 2017. Police in Barcelona said they were dealing with a "terrorist attack" after a vehicle ploughed into a crowd of pedestrians on the city's famous Las Ramblas boulevard on August 17, 2017. Police were clearing the area after the incident, which has left a number of people injured. / AFP PHOTO / Josep LAGOJOSEP LAGO/AFP/Getty Images AFP/Getty Barcelona Attack A man displays flowers at the Canaletas fountain on the Rambla boulevard on August 18, 2017, a day after a van ploughed into the crowd, killing 13 persons and injuring over 100 on the Rambla in Barcelona. Drivers have ploughed on August 17, 2017 into pedestrians in two quick-succession, separate attacks in Barcelona and another popular Spanish seaside city, leaving 13 people dead and injuring more than 100 others. In the first incident, which was claimed by the Islamic State group, a white van sped into a street packed full of tourists in central Barcelona on Thursday afternoon, knocking people out of the way and killing 13 in a scene of chaos and horror. Some eight hours later in Cambrils, a city 120 kilometres south of Barcelona, an Audi A3 car rammed into pedestrians, injuring six civilians -- one of them critical -- and a police officer, authorities said. / AFP PHOTO / Josep LAGOJOSEP LAGO/AFP/Getty Images AFP/Getty Images Barcelona Attack TOPSHOT - The van who ploughed into the crowd, killing at least 13 people and injuring around 100 others is towed away from the Rambla in Barcelona on August 18, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". The driver of a van that mowed into a packed street in Barcelona is still on the run, Spanish police said. / AFP PHOTO / Josep LAGOJOSEP LAGO/AFP/Getty Images AFP/Getty Barcelona Attack TOPSHOT - Forensic policemen arrive in the cordoned off area after a van ploughed into the crowd, killing 13 persons and injuring over 80 on the Rambla in Barcelona on August 17, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". / AFP PHOTO / Josep LAGOJOSEP LAGO/AFP/Getty Images AFP/Getty Images Barcelona Attack TOPSHOT - A person is helped by Spanish policemen and two men after a van ploughed into the crowd, killing at least 13 people and injuring around 100 others on the Rambla in Barcelona on August 17, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". The driver of a van that mowed into a packed street in Barcelona is still on the run, Spanish police said. / AFP PHOTO / Nicolas CARVALHO OCHOANICOLAS CARVALHO OCHOA/AFP/Getty Images AFP/Getty Images Barcelona Attack TOPSHOT - Policemen accompany clients of a store outside a cordoned off off area after a van ploughed into the crowd, killing 13 persons and injuring over 80 on the Rambla in Barcelona on August 17, 2017. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". / AFP PHOTO / LLUIS GENELLUIS GENE/AFP/Getty Images AFP/Getty Images Barcelona Attack TOPSHOT - Forensic policemen arrive in the cordoned off area after a van ploughed into the crowd, killing at least 13 people and injuring around 100 others on the Rambla in Barcelona. A driver deliberately rammed a van into a crowd on Barcelona's most popular street on August 17, 2017 killing at least 13 people before fleeing to a nearby bar, police said. Officers in Spain's second-largest city said the ramming on Las Ramblas was a "terrorist attack". The driver of a van that mowed into a packed street in Barcelona is still on the run, Spanish police said. / AFP PHOTO / PAU BARRENAPAU BARRENA/AFP/Getty Images AFP/Getty Images

Spain announced in 2015 that it would not join the US-led air campaign against Isis in Iraq and Syria. It has an army training team in Iraq but its members do not take part in combat.

In 2003 the Aznar government had sent a small force to join the Iraq invasion. Twelve years later Mr Aznar was claiming that “in terms of international support for our goals, Spain emerged a winner”. In 2005 a Spanish parliamentary panel investigating the Madrid bombing concluded that the Aznar government had “manipulated” and “twisted” information to blame the Basques rather than al-Qaeda for the attacks.