Here are excerpts from Metropolitan Police records of the coded messages between Rajib Karim and his brother Tehzeeb.

The Crown said correspondence to and from the radical preacher Anwar al-Awlaki (occasionally referred to as ''prof'') are also contained within the brothers' messages.

:: January 25, 2010 From al-Awlaki to Karim: ''... depending on what your role is and the amount of information you can get your hands on, you might be able to provide us with critical and urgent information and may be able to play a crucial role for the ummah...

''I was pleased when your brother conveyed from you salaams to myself and was excited by hearing your profession. I pray that Allah may grant us a breakthrough through you. As a starter, can you please answer these questions in as much elaboration as possible: can you please specify your role in the airline industry, how much access do you have to airports, what information do you have on the limitations and cracks in present airport security systems, what procedures would travellers from the newly listed countries have to go through, what procedures would a person on a watch list have to go through?''

:: January 29, 2010 From Karim to the ''prof'', alleged to be al-Awlaki: ''It has been three years that I have been living here away from the company of good brothers and spending a good part of my day working with the kuffar. I was also keeping a low profile by hiding my real religious viewpoints, trimming my beard and not getting too involved in the local Muslim community or any Islamic activities. But leading a life like that was really killing me inside, that's why I desperately wanted to make hijrah as I was not seeing any opportunities to do anything in this land...

''I have knowledge about the key people in BA starting from the top management and the key people in BA IT department. I also have knowledge about key IT hardware locations, which if targeted can bring huge disruption to flights and cause BA a major financial loss ... but this would be at the risk of exposing myself as I will have to do that with my own login ID...

''I personally know two brothers, one who works in baggage handling at Heathrow and another who works in airport security. Both are good practising brothers and sympathise towards the cause of the mujahideen and do not slander them. They are of the type who would help with money and moral support but I am not sure if they are at the stage to sacrifice with their lives.''

:: February 13, 2010 From al-Awlaki to Karim: ''Our highest priority is the US. Anything there, even if on a smaller scale compared to what we may do in the UK, would be our choice. So the question is: with the people you have, is it possible to get a package or a person with a package on board a flight heading to the US? If that is not possible, then what ideas do you have that could be set up for the uk?''

:: February 15, 2010 From Karim to his brother, Tehzeeb: ''If it's not a good idea to visit you guys, then I intend to visit BD or USA. If I visit USA, I can check out what their security process is like.''

From Karim to al-Awlaki: ''I have started working on the bros I mentioned on the last letter without mentioning you directly. Alhamdulillah the bros responded better than I expected...

''Like you say, I also agree that US is a better target than UK, but I do not know much about US. I can work with the bros to find out the possibilities of shipping a package to a US-bound plane.''