By Gordon Corera
BBC News security correspondent, Islamabad
Tanvir Hussain, Abdulla Ahmed Ali and Assad Sarwar were found guilty
The liquid bomb plot, which has resulted in three significant convictions for conspiracy to murder, was al-Qaeda's most ambitious attempt to target the West since 9/11.
In recent years the UK has witnessed a spectrum of attempted attacks - ranging from home-grown, unconnected amateurish individuals at one end, to international conspiracies apparently directed by al-Qaeda's leadership at the other.
This plot appears to sit at the far end of the scale in terms of ambition and organisation, although the jury at Woolwich Crown Court failed to reach verdicts on four of the defendants, or on the most serious allegation against the three main defendants that the plot was to bring down airliners.
Senior counter-terrorism officials describe it as the "pinnacle" of a series of continuing threats to the UK that began in 2004 and originate from al-Qaeda in Pakistan.
Eight out of 10 top priority terrorist investigations in the UK have some connection to Pakistan, according to a number of counter-terrorism officials.
Threats have emerged from other parts of the world, including east Africa, and also from entirely self-sufficient home-grown individuals.
But officials say these threats do not have the severity of those coming out of Pakistan. And it is the latter that have the potential to have "strategic impact", say officials.
Western counter-terrorism officials debate the degree to which al-Qaeda remains able to provide real command and control over plots.
Some think this ability has diminished recently but it is clear that the liquid bomb plot does show a strong connection not just to Pakistan but to al-Qaeda's leadership.
In the case of this plot, the connections to Pakistan were crucial. The ringleader, Abdulla Ahmed Ali, travelled out a number of times. Material for the plot was brought back along with the technology of liquid explosives tested in Pakistan.
In Pakistan, a British man from Birmingham called Rashid Rauf is believed to have put plotters in touch with al-Qaeda's leadership.
Rashid Rauf escaped from police custody while visiting a mosque
Mr Rauf remains at large after escaping from arrest. In a small Islamabad police station, I was shown the case file regarding his escape. Officials put it down to incompetence, claiming they were not informed of his importance.
But back in London, British officials speak of Rashid Rauf being of "immense interest" because of his links to a string of conspiracies.
They think his detention would make a real difference - but privately many officials in both London and Islamabad concede that they are unlikely to ever find Mr Rauf again.
With or without Mr Rauf in a jail cell, officials now have quite a clear idea of how many of these plots have come together.
Individuals have typically radicalised in the UK and later travelled to Pakistan and come into contact with al-Qaeda through a trusted contact.
It is this link-up that means they gain training, motivation and the ability to carry out attacks of a sophistication they would never be capable of on their own.
We now know of some individuals who planned to fight what they regarded as a legitimate jihad in Afghanistan were guided towards attacking the UK instead.
The suicide bomber Mohammad Sidique Khan, the ringleader of the 7 July attacks in 2005, was one of them. He left the UK in 2004, preparing to die on the battlefield alongside the Taleban - he even recorded a farewell video for his baby daughter.
The draw of jihad in Afghanistan is getting stronger and has easily replaced Iraq as the place where individuals go, seeking to enhance their status by fighting against the West.
And, according to debriefings of senior al-Qaeda detainees, Britons remain keener than any other nationality, including other Europeans, to go to Pakistan and fight - or to seek opportunities to link-up with al-Qaeda.
Once fired up, these individuals set out to recruit followers back in the UK to carry out their attacks.
During the past five years, the threats have evolved in terms of ambition and sophistication, with a shift from amateurish fertiliser-based explosives to sophisticated chemistry based on hydrogen peroxide, a form of hair bleach.
Bottles containing hydrogen peroxide were presented as evidence in the trial
At the same time, the operational security of the plotters has also notably increased.
However, the targets of the plots have remained relatively consistent, including transport and particularly airports and airlines.
But the timetable between radicalised individuals returning from Pakistan and planning their attack has shortened, making investigations harder and more intense for British intelligence and security services.
There are also tantalising connections between many of those involved in the major plots in the UK.
Mohammad Sidique Khan knew the 2004 fertiliser bomb plotters.
Abdulla Ahmed Ali was in phone contact with the leader of the 21 July failed attack, Muktar Ibrahim.
All three men were in Pakistan at the same time in late 2004. All returned to plan attacks with bombs based on hydrogen peroxide, devices not used before in the UK.
Counter-terrorism officials cannot be sure, but speculate that they may have all been trained by the same al-Qaeda operative.
Osama Bin Laden is thought to be in hiding near the Afghan-Pakistan border
All of these plots may have been overseen by a man called Abu Obeida al-Masri, the former head of al-Qaeda's external operations who is thought to have died of natural causes earlier in 2008.
He was thought particularly effective at working with Western recruits because he had lived in Europe.
So what does all of this tell us about the threat from al-Qaeda?
It's unclear whether such plots would need approval from Osama Bin Laden or Ayman Al-Zawahiri, the two top figures who are thought to be isolated and hidden away in the Afghan-Pakistan border areas.
There has been a relative lull in high-end attacks but counter-terrorism officials believe it is premature to say al-Qaeda is seriously damaged, particularly when Pakistan's own security situation is so uncertain.
The liquid bomb plot might have been hatched at a time when pressure on al-Qaeda in the tribal areas was reduced.
Officials are concerned that the foot could again go off the accelerator in Pakistan now.
Their hope is to maintain pressure in a way that makes al-Qaeda worry about its own day-to-day survival rather than have the time and space to plan attacks around the world.