When the factory was found on 12 July, much of the bomb-making equipment was still there.

It is thought that each device consisted of 2-5kg of explosive and that the group used details from "open sources" like the internet and also had advice from someone with experience.

The ingredients would have had a strong bleaching effect and the families of both Tanweer and Hussain said they had noticed that their hair had become lighter.

This X-ray image of a nail bomb linked to the 7 July attacks showed the bombers' murderous intent.

Police found a number of devices in a car rented by one of the suicide bombers and left near Luton rail station.

All the items contained peroxide-based explosives, used in the 7 July bombs, and two were "live" devices.

It is not clear what these items - thought to be detonators - or any of the rest were doing in the car.

It is not known if the stash had been left for other people, or even if the bombers intended to return.

Whoever they were meant for, this device with orange ball bearings attached clearly shows the maker's intention.