Bilal Abdulla, 29, wrote of his ability to "lick the blood" of westerners, adding that a population "busy with alcoholic drinking and with their intimate friends" could only be awakened "by the sound of booby traps".
Earlier in the day, a jury at Woolwich Crown Court heard that his alleged accomplice, who died in an attempted strike at Glasgow Airport on 30 June last year, had sent a separate will to his brother, in which he warned of "hitting the devils' place".
Abdulla is accused of being a member of an Islamic terrorist cell that plotted mass murder with a series of car bombs.
He is alleged to have driven one of two Mercedes cars laden with gas canisters to a club in London's West End, the court has been told. When they failed to detonate, he is said to have joined a suicide attack on Glasgow Airport the following day in which Kafeel Ahmed later died.
Abdulla is on trial with a second man, Mohammed Asha, 28, accused of conspiracy to murder and cause explosions. Both men deny the offences.
In court yesterday, evidence taken from a laptop found in the burnt-out Jeep was given. Detective Constable Graeme Burridge, a forensic computer examiner, said he was able to recover files from the recycle bin and hard drive of the computer. The documents were written and edited by Abdulla, the court heard.
One such document, described as Abdulla's draft will, had been created over a period of 455 minutes and been revised 39 times.
It is addressed to a number of recipients, including "Osama" and "our soldiers of Islam in the country of the two rivers" – a reference to fighters in Iraq, the jury was told.
In it, Abdulla is alleged to have written that he wanted to announce "the news of victory and glorious conquests at the heart of the state of unbelievers and tyranny".
The draft will continues: "God has blessed us the ability to lick the blood of the Romans (a reference to westerners] as you have done before us in the past."
The court heard Abdulla went on to rail against "the Kingdom of Evil".
He is alleged to have written: "It destroyed our caliphate, tore apart our unity, defamed and distorted our religion and stabbed us in the heart the day it established that infernal state in our Palestine."
The court was told that, in a reference to conflicts in Iraq and Afghanistan, he wrote: "Their soldiers kill the young and old. They do not discriminate between men and women, so why should we? If the policy of their army is to kill women and children, then only a similar policy would deter them."
The draft will hold the entire population responsible for the action of its government.
"These people do not care about what is happening in our land as they are all busy with alcoholic drinking and with their intimate friends…these people can only be awakened by the sound of booby traps and the Mujahideen hailing 'God is great'."
In separate letters, he praised Islamist fighters in Iraq and called on the Muslim community in Britain to "leave this land of unbelievers and atheism before losing your religion".
Another document recovered from the laptop contained a transcript of an interview with Abu Musab al-Zarqawi, the former head of al-Qaeda in Iraq, the court heard.
Abdulla is also alleged to have been the author of a letter purporting to be from his sister to the doctor's supervisor at the Royal Alexandra Hospital in Paisley. In the missive recovered from the computer, the hospital line manager is told Abdulla will not be able to come to work due to an overseas accident in which he had been left paralysed.
The letter was last edited on 30 June, the expert witness said, the day of the Glasgow attack.
The jury heard that Kafeel Ahmed, who died as a result of burns received when the Jeep caught fire, had left a will to his family before the attacks.
In it, he wrote that the "call of Jihad" had been "loud and open" and also apologised for lying to his family.
The letter read: "I seek forgiveness from all of you for not informing and for lying about a lot of things. It was only because it was necessary for the safety and security."
It continued: "Me and some brothers were given the opportunity to hit the devil's place. The core. And this is what we have tried by the help of Allah."
In a message to his mother, he added: "You know the pain and cries of our brothers and sisters, and someone has to do something. Why someone else, why not your own son? So be generous and sacrifice your son for the sake of Allah."
The trial of Abdulla and Asha continues.
BILAL ABDULLA: Accused had worked at the Royal Alexandra Hospital as a junior locum, having studied medicine at the University of Baghdad, Iraq.
He allegedly met several other of the suspects involved in the attacks while living in Cambridge, where he attended the city's Abu Bakr Jamia Siddiq Mosque, and was known for being knowledgeable on the Koran.
MOHAMMED ASHA: Born in Jordan, he lived in Newcastle-upon-Lyme, Staffordshire.
He was arrested by police hours after the Glasgow Airport attack, while travelling on the M6 with his wife, Marwa.
The doctor specialised in neurological surgery and had been working at a local hospital. He also once worked at the Addenbrooke's Hospital in Cambridge.
KAFEEL KHALID: The 27-year-old driver of the green Jeep Cherokee used in the Glasgow Airport attack, and who subsequently died from his injuries. He studied at Queen's University in Belfast and Anglia Polytechnic University in Cambridge.