Eight Islamic fanatics plotted to kill thousands of passengers "on an almost unprecedented scale" by boarding flights out of London with home-made bombs, a court was told.

At least seven aircraft flying to major cities across North America were the target of the sophisticated conspiracy, a jury heard yesterday. Prosecutors said suicide bombers would smuggle liquid explosives disguised as soft drinks on to the flights at Heathrow Airport.

They then planned to detonate the deadly devices within hours of each other leaving the authorities powerless to act.

Peter Wright QC, prosecuting, described the defendants as having the "cold-eyed certainty of the fanatic".

He told Woolwich Crown Court an "unwitting civilian population" would be the victim of the murderous plot devised in the name of Islam. Mr Wright said: "What these men intended to bring about was a violent and deadly statement of intent that would have truly global impact."

He added: "These men and others were actively involved in a deadly plan designed to bring about what would have been, had they been successful, a civilian death toll from an act of terrorism on an almost unprecedented scale.

"Fortunately they were arrested before they could put those plans into effect."

Eight men deny conspiring to murder and to endanger the safety of an aircraft between January and August 2006.

They are Mr Ali, aka Ahmed Ali Khan, 27, of Walthamstow, east London; Mr Sarwar, 27, of High Wycombe, Buckinghamshire; Tanvir Hussain, 27, of Leyton, east London; Mr Gulzar, 26, of Barking, east London; Ibrahim Savant, 27, of Stoke Newington, north London; Arafat Waheed Khan, 26, of Walthamstow; Waheed Zaman, 23, of Walthamstow and Umar Islam, aka Brian Young, 29, of Plaistow, east London.

The jury was told three men were at the centre of the plot: Abdulla Ahmed Ali, Assad Sarwar and Mohammed Gulzar.

Mr Wright said undercover counter-terrorist police watched Mr Ali and his alleged conspirators for months. He said as officers gathered information they realised the men were planning a terrorist atrocity.

They often met at a flat in Forest Road, Walthamstow, where police later discovered what they believed to be bomb-making materials. He said officers swooped on Mr Ali as he met Assad Sarwar, in a public car park in Walthamstow on August 9, 2006. In his pocket they found a computer memory stick containing details of one-way flights from Heathrow Airport.

Seven scheduled flights on three carriers departing each day within two-and-a-half-hours from terminal three were highlighted. The destinations were San Francisco, Toronto, Mont-real, Washington, New York and two services to Chicago.

Mr Wright added there was evidence the accused had ambitions to bring down more than just seven aircraft. He said a conversation between two of the men revealed they also considered other terminals and as many as 18 suicide bombers.

The jury were given details of the how the men planned to make undetectable bombs from common household materials.

The prosecution said a "blueprint" of the plot was found handwritten by Mr Ali in his diary. Pages from the diary refer to how the materials for the bombs were to be smuggled on to the aircraft, Mr Wright said.

Mr Ali wrote how he planned to carry a "dirty mag to distract" and a condom, the jury was told. On one page he wrote: "Decide on which battery to use for D, small is best". In another entry he added: "Select date, five days before jet. All link up." He also wrote: "One drink use, other keep in pocket, maybe will not get through. Plus keys and chewing gum on the D in the electronic device."

Mr Wright said the diary entries clearly showed how Mr Ali intended to execute the bomb plot. The main agent in the home-made explosives would be hydrogen peroxide mixed with other chemicals, the jury was told. The liquid explosive, mixed with a sugary drink known as Tang, would be injected into 500ml plastic bottles of Oasis and Lucozade.

This main charge would be detonated by another home-made substance known as HMTD concealed within AA 1.5v batteries, Mr Wright said. The prosecutor said improvised bombs using similar ingredients have been used in other terrorist attacks.

The detonator would then be ignited using metal wire, a small bulb or the flash from a disposal camera, he said.

The trial continues.