Mr Justice Henriques told the trio that they will all face life in prison when they are sentenced in April or May.
Speaking to Naseer, he said he had been convicted on "overwhelming evidence" and that he will face "a very long minimum term".
The judge said: "
You are a highly skilled bomb maker and explosives expert. Your mindset was similarly manifest.
You sought to persuade others that a terror plot here in this country was by far preferable to fighting jihad abroad.
The scale and extent of your ambition was similarly manifest. You were seeking to recruit a team of somewhere between six and eight suicide bombers to carry out a spectacular bombing campaign, one which would create an anniversary along the lines of 7/7 or 9/11.
It's clear that you were planning a terrorist outrage in Birmingham.
The judge told Khalid he was "virtually inseparable" from Naseer.
You were very much his confidant and his right-hand man.
He said to Ali:
I had mistakenly formed the view that you were a rather foolish recruit to this terrorist cell and rather less dangerous than your co-accused.
You have dissuaded me from that view. You are intelligent, devious and highly manipulative.