With alleged Algerian extremists facing terror charges across Europe, the BBC's Andrew Hosken visits Algeria to investigate how the country's long civil conflict has changed the nature of Islamic militancy.
The effects of Algeria's civil war are now being felt abroad too
It has been called "La Sale guerre" (the Dirty War), a civil war fought with astonishing ferocity that has lasted more than a decade.
Around 150,000 people have been massacred in Algeria since 1993.
The latest atrocity occurred on 11 February when 12 people were murdered at a bogus road block near the village of Hameur El Ain in the Tipaza region, 70 kilometres (44 miles) outside of Algiers.
Again the authorities blamed "Islamic extremists". The truth is more chilling.
It is becoming clear that the Sale guerre is not just a matter for the Algerians but that it may now have spilled over into Europe
The militants and the army have long blamed each other for the killings.
The government has even been accused of operating death squads.
It has strenuously denied the allegations.
The roots of the conflict lie in early 1992, with the decision of the army to suspend elections in which a hardline Islamic party, the FIS, won a major victory in the first round.
The leaders of the FIS were thrown in jail, where they remain.
Decade of war
For almost a decade, foreign journalists were discouraged from covering the conflict.
Islamic militants ordered all foreigners to leave the country in the mid-1990s and followed up their threat by killing some who failed to take the threat seriously.
It is becoming clear that the Sale guerre is not just a matter for the Algerians but that it may now have spilled over into Europe.
The war shows no sign of ending
It is not the first time this has happened.
In 1995, Algerian militants belonging to the GIA (Armed Islamic Group) launched bomb attacks against the Paris Metro.
The militants were angered by the support the French gave to the Algerian Government.
Now, with the arrests of suspected Algerian militants in Britain and across Europe, there is increasing interest in the conflict.
The British Government has confirmed that it is receiving assistance from the Algerian intelligence services.
Brian Wilson, the energy minister, recently visited Algiers as part of a British business delegation.
He told the BBC's Today Programme that, for years, the government had failed to take much notice of warnings by the Algerians about some of those granted asylum in Britain.
He said that Britain was now receiving help from the Algerian Government.
In Algeria, Mr Wilson met his counterpart, Dr Chakib Khelil, who said that European governments had ignored warnings for years.
He said that it often took certain governments direct experience of terrorism or attempted terrorism before such warnings would be taken seriously.
The prospect of Britain working closely with Algeria has caused some alarm.
"Le Pouvoir" ("The Power") which controls Algeria has a poor record on human rights.
Controlled mainly behind the scenes by unelected generals, the government has been accused of extra-judicial murder, torture and abduction.
In an oil-rich country, Algerians remain poor
More than 4,000 people have "disappeared".
The relatives of the disappeared protest each week outside the Human Rights Ministry in Algiers but there are no answers.
The government has told them to move on, that "the past is dead".
The truth is, though, that the war continues and that the "disappeared" are almost certainly dead.
Algeria is one of the richest countries on the African continent.
It is the second biggest exporter of natural gas to the European Union.
Huge natural resources remain to be exploited.
But, despite that, millions of Algerians live in poverty.
Some areas suffer from 30% unemployment.
It is not unknown for families of 10 or more to live in a one-bedroomed flat.
The government in Algeria insists that it is desperate to deflect people from terrorism and stop the exodus abroad.
It knows that the only way to do that is to provide homes and jobs.
Algeria has a population of 32 million. An astonishing 60% are under 20 years of age.
Many find it impossible to start families of their own while squashed into tiny homes with the rest of their family.
While the vast majority of Algerians are sick of the militants and the alleged corruption of the "Pouvoir", a tiny minority have joined the militants - some through religious zealotry, others through sheer anger.
The main militant organisation, the GIA, has largely disbanded following an amnesty brokered by the army
four years ago.
But the GSPC (the Salafist Group for Preaching and Combat), another grouping of Islamic fundamentalists, continues to fight.
It is the GSPC which is causing Western governments such alarm.
In Algeria, the GSPC claims that it has confined its activities to killing soldiers and policemen.
Indeed, it recently ambushed and killed 40 soldiers.
A policeman was shot in the centre of Algiers earlier in February.
But the Algerian Government and some intelligence agencies claim that it has now teamed up with al-Qaeda to launch attacks abroad.
Some senior generals of the Pouvoir say they have defeated the militants but that Islamic fundamentalism remains intact.
That, again, appears to be only half-true, as the recent massacre at the false road block has only too clearly demonstrated.