London flat 'used to turn flour and hair dye into explosives'

In the early part of 2005, a one bedroom council flat in Curtis House - a tower block just off the North Circular Road in Southgate, north London - became the "bomb factory" for the attempted suicide bombings of 21 July, the jury at Woolwich Crown Court was told.

The flat, home to Yassin Omar, one of the six men accused of murder and conspiracy to murder, was used as a meeting place for at least four of the men, and was where they made the five bombs using material purchased from local shops.

Nigel Sweeney, prosecuting, said that purchasing for the bombs began in late April or early May of 2005. A total of 284 bottles containing 443 litres of hydrogen peroxide, a chemical used to dye hair, was bought under the pretext it was being used for stripping wallpaper or bleaching wood.

The jury was told that, using two saucepans and a frying pan on the flat's small cooker, the men set up a seven-day rota involving Ibrahim, Asiedu and Omar to oversee the process of boiling it down to the required concentration. Some was re-bottled with labels suggesting it had reached the required strength. Subsequent test firings by forensic scientists suggested that one reason why the bombs had not fully exploded could have been that the chemical had not been sufficiently reduced.

Mr Sweeney said the reduced chemical was then mixed with chapati flour to form the bulk of the explosive. Detonators were made from cardboard tubes filled with triacetone triperoxide (TATP), an explosive made from hydrogen peroxide, acetone and acid. They were to be ignited using torch bulbs connected to a small battery by long wires and a snap connector, all of which were also bought from nearby shops.

Each bomb was packed into a 6.2 litre plastic container, to the outside of which was fixed a large quantity of screws, tacks, washers and nuts. Holding up a replica, Mr Sweeney said: "The purpose of shrapnel is, of course, to increase fragmentation when the bomb explodes and thus to maximise the possibility of injury, fatal or otherwise, to those in the vicinity.''

The bombs had been carried in rucksacks from which two wires protruded through slits in the back. These in turn led unobtrusively into the clothes of the men, who would appear to be carrying an ordinary rucksack.

"At the moment of his choosing, he could bring the snap connector into contact with the nine volt battery and set off the bomb," Mr Sweeney said.