A friend of the alleged July 21 terror plotters told a court today how he helped to collect the main ingredient for bombs, believing it was to be used for decorating.

Product designer Matthew Dixon said he drove Manfo Kwaku Asiedu, the alleged fifth bomber, to a hairdressing wholesalers in north London to pick up bleach for "stripping walls in listed buildings".

But when the pair were asked by the sales assistant what the substance was for, Asiedu "seemed a bit reluctant to answer", Woolwich Crown Court was told.

Mr Dixon said when they were advised the liquid peroxide was volatile, Asiedu replied: "No worries."

The court has already heard how Asiedu bought 16 litres of hydrogen peroxide, allegedly for use as an explosive charge, on May 19, 2005.

Mr Dixon said Asiedu told him the wallpaper was so thick, ordinary wallpaper stripper wouldn't work.

The court heard how Mr Dixon had been reluctant to go on the shopping trip because he was busy, but Asiedu had been "persistent". Mr Dixon said: "He said I was the only person he knew with a car."

Asked if he knew at that time of the potential use of peroxide in explosives, Mr Dixon said: "Of course not."

Asiedu, 33; Muktar Said Ibrahim, 28; Ramzi Mohammed, 25; Yassin Omar, 26; Hussain Osman, 28; and Adel Yahya, 24 all deny conspiracy to murder and conspiracy to cause explosions.

The trial continues.