The trial of six Muslim extremists' accused of attempting a wave of coordinated suicide attacks heard how a Finchley shop unwittingly sold the key ingredient for bombs intended to kill and maim people.

Manfo Kwaku Asiedu, 33, who temporarily lived in Ballards Lane, Finchley, is alleged to have bought 120 litres of hydrogen peroxide from Sally's Hair & Beauty Supplies, also in Ballards Lane. The prosecution says the liquid hydrogen peroxide was later mixed with chapatti flour at a council flat in Curtis House, Ladderswood Way, New Southgate, to make bombs for an assault on London's transport network on July 21, 2005.

Woolwich Crown Court heard from Sandra Sealey, manager of Sally's, who said she had no idea hydrogen peroxide could be used to make a bomb. Asiedu allegedly ordered the hydrogen peroxide on June 21, 2005, picking it up nine days later and paying in cash. The shop had slashed the price of the one-litre bottles from £2.98 to 99p, the court heard.

Asked if she had asked Asiedu why he wanted such a large amount, Mrs Sealey told the court: "I asked him what it was for and he said it was for stripping paint." Mrs Sealey described how she had looked quizzically at her sales assistant, Orlando Baghaloo, then put the order through.

Mrs Sealey said she had later told Mr Baghaloo: "He must be doing a lot of decorating." On Monday, the jury heard how one of the defendants, Yassin Omar, 26, made a goodwill visit to a retired Christian bishop at Barnet Hospital. Matthew Dixon, a friend of Omar's, told the court Omar disagreed with the bombings carried out by Islamic extremists in London on July 7, 2005. Mr Dixon also said Omar, who lived at the Curtis House flat and previously attended Enfield College, visited the retired bishop in hospital and looked after a man with mental difficulties at the flat in New Southgate.

The court heard Mr Dixon said to police: "Yassin has always said the whole idea of Islam is to bring people to it and he has always been a strong believer that these kind of attacks on people do not achieve anything, they just alienate people from the religion'.

Asiedu and Omar deny conspiracy to murder and conspiracy to cause explosions likely to endanger life. Also denying the charges are co-defendants Hussain Osman, 28, of Blair House, Stockwell Road, Stockwell; Ramzi Mohammed, 25, of Dalgarno Gardens, Peabody Estate, North Kensington; Adel Yahya, 24, of High Road, Tottenham; and Mutkar Said Ibrahim, 28, of Farleigh Road, Stoke Newington.

The trial continues.