The terror plot for which three men have now been convicted showed a change in the way al Qaida is operating, a counter-terrorism expert said.
Irfan Naseer, 31, and Irfan Khalid, 27, both travelled to terrorist training camps in Pakistan between 2009 and 2011 to learn about bomb-making, poisons and firearms.
But once they returned to Britain, they were left to set up their own domestic terror network and carry out their attacks.
This marks a departure from previous plots such as the plan to bomb airliners which was uncovered in 2006, where ringleader Abdulla Ahmed Ali had regular contact with mystery terrorist contacts in Pakistan.
Raffaello Pantucci, a senior research fellow at the Royal United Services Institute, said the change is partly because camps in the mountainous region of Waziristan in Pakistan are under increasing threat of drone strikes.
He said: "We have seen this trend starting to emerge for a while. If you look back in time you can see how the time spent training foreign fighters by al Qaida or affiliated networks is now being constrained because there is the threat of drone strikes. The command and control element is drawing back.
"I think the conclusion for the security services is that the pressure in Waziristan is working."
This means that trainees in the terror camps are often less effectively prepared because they have less time to learn.
Pantucci said: "It has a negative impact on their capacity to launch attacks because people aren't being trained as well.
"There is sometimes a clownish element to it."
In the 2006 plot, police said the plan was drawn up in Pakistan with detailed instructions passed to Ali during frequent trips to its lawless border with Afghanistan.
They believed a mystery al Qaida bomb-maker was responsible for a liquid bomb design which was to be concealed within 500ml Oasis or Lucozade bottles.
After he returned to the UK, Ali was watched as he used public phone boxes, mobile phones and anonymous email accounts to keep in touch with terrorist controllers in Pakistan.
(Left to right) Irfan Naseer, 31, Irfan Khalid and Ashik Ali, both 27
Pantucci said: "You can draw the conclusion that there was a very close connection, that connection can't really exist any more."
In the current case, there was also surprise in counter-terrorism circles at the apparent speed and ease with which Naseer and Khalid were able to link up with al Qaida and obtain training, despite arriving in Pakistan with no previous contacts.
The pair flew to Pakistan via Istanbul in Turkey on Boxing Day 2010, and spent around three months in the Karachi area before moving on to Waziristan.
There they made contact with al Qaida, and were given training in how to use explosives, firearms and poisons.
Khalid and Naseer made martyrdom videos, which were not recovered but were mentioned in conversation, while they were there, which they left with their contacts for release once the attacks had been carried out.