"You love life and we love death." The chilling phrase leaps out of the video issued by a man calling himself al-Qaeda's military commander in Europe.
Al-Qaeda's attack could have had political motive
These words have been repeated many times in the past two and half years - in audio tapes, emails and interviews emanating from Osama Bin Laden and his lieutenants.
They are certain that their willingness to lose their own lives in order to kill as many innocents as possible in spectacular terror attacks will ultimately deliver them victory in the war of attrition they declared against "the Jews and the Crusaders" back in 1998.
The American declaration of a "war against terror" in the aftermath of the 9/11 attacks played into Bin Laden's strategic goal of creating a pan-Islamic empire harking back to a medieval caliphate.
The war in Iraq has presented a new opportunity for a battered al-Qaeda to swell its depleted ranks with new recruits and offshoot organisations.
In many Muslim minds it has aggravated the already festering sore of the Israel-Palestine conflict.
And now the Madrid bombings have given al-Qaeda its biggest political coup to date - the power to swing an election in Europe.
Since the ousting of the Taleban from Afghanistan in 2001, al-Qaeda's leadership has been under pressure and on the run.
However, back in the spring of 2002 an American intelligence officer at Bagram airbase told BBC's Panorama that he feared the American military boot had not crushed al-Qaeda but merely scattered them to the far corners of the earth, where they would prove impossible to eradicate.
How right he was. The following 12 months saw more carnage - in Bali, east Africa and on the shores of the Mediterranean. Al-Qaeda has never been a single organisation - its name means "the base" - and Bin Laden has always seen it as an umbrella for disparate extremist Islamist groups.
But since 9/11 and the destruction of its geographical centre in Afghanistan, al-Qaeda has become a global movement, a franchise operation that no longer depends on the centre for military and financial backing.
Much is made by western governments of al-Qaeda's inability to fight a war now its training camps have been destroyed. But there are signs of similar small-scale facilities cropping up once again either side of the border between Pakistan and Afghanistan.
And an estimated 15,000 men passed through the camps before they were obliterated.
Al-Qaeda has never in the past adhered to western timetables or anniversaries. It has been content to wait and plan patiently for the best moment and place to strike.
The Istanbul bomb came as Bush and Blair gathered at an anti-terrorism gala
But recently the terror group gave notice of a more carefully honed political sense when one of its local affiliates bombed the British Consulate in Istanbul in November.
The attack came on the very day that George Bush and Tony Blair were celebrating their special relationship and their determined stance against terrorism at a glittering state gala in London.
In December, meanwhile, on Islamic websites that have carried al-Qaeda statements in the past, Islamist militants were discussing how attacks might bring about a socialist victory in Spain and the withdrawal of Spanish troops from Iraq.
There was speculation that such an event would increase the pressure on Blair to pull out British troops. If they were feeling bold enough then to try to influence the outcome of democratic elections, how much bolder will they feel now?
For years, Bin Laden has been exhorting his followers to oust what he calls corrupt Arab regimes in Saudi and the Gulf states. His chance of success in undemocratic states with efficient and ruthless police forces was slim.
It is so much easier not only to hit "soft" targets such as railway trains but also to influence what al-Qaeda sees as soft political targets - namely, European democracies.
The reaction to the Spanish bombings in Britain has built slowly over the past few days, as al-Qaeda is identified as the likely culprit.
Alerts on the London underground and headlines about white powder sent to embassies show how anxiety is building to levels unseen since the aftermath of the 9/11 attacks.
Yet in this war it is impossible to gauge how close this country is to becoming the next target, beyond Bin Laden's repeated threat that Britain is at the top of his hit list.
The frozen, haunted look on Bush's face as an aide whispered news of the World Trade Centre attack was echoed on the face of the defeated Spanish prime minister José María Aznar at the Madrid vigil.
Tony Blair knows and fears that look, and cannot afford to dismiss lightly any information gleaned by his intelligence and police chiefs.
Eighteen months ago, it was a threatened surface-to-air-missile attack on Heathrow airport over which the security forces sweated. Just such an attack had been tried in Mombasa in Kenya, although luckily it failed.
People laughed and accused politicians of cynical manipulation when tanks were deployed around the airport, but the threat was real.
At least two suicide bombers are known to have been recruited in the UK by Bin Laden's former military commander, Khalid Sheikh Mohammed. Those men have not yet been found.
On the other hand, there have been incidents here that are more difficult to read. A crude laboratory, allegedly to make the biological poison ricin, was uncovered in Wood Green, London, in January 2003.
A group of Algerians were arrested, but so far there have been no terror-related charges and the ricin scare may well turn out to have been overblown.
The Iraq war could have led to more al-Qaeda recruits
The controversial British anti-terrorism legislation of 2001 has had an effect that has heartened many in the security community.
Some of the top figures on the suspects list were rounded up and disappeared into Belmarsh Prison. Others hastily chose to take "extended holidays" to places such as Pakistan and have never reappeared.
But this legislation worries many liberal-minded citizens across the political divide, as does the threatened backlash that terror brings against our long-established and law-abiding Muslim communities.
Bin Laden was mocked last spring for not immediately carrying out his much-vaunted threat to make the earth burn beneath the boots of US and British soldiers.
Winning the war?
Yet as the months have passed the war in Iraq has exposed the hollowness of US claims that al-Qaeda and Saddam were linked.
It has also resulted in the creation of a new terror threat from one of al-Qaeda's franchises, and a virulent and deadly one that numbers hundreds of westerners among its victims.
A very real terror threat has been created in Iraq where little existed before - and Europe will feel the effect of that.
Bin Laden has every reason to believe that he is so far winning the battle - not the "war on terror" waged by US helicopters and special forces on Afghan borders - but the war against innocent civilians and western democracies .
Panorama: Terror - Are We Next? was broadcast on BBC One on Sunday, 21 March 2004 at 2215 GMT