LONDON, July 15: The powerful explosive TATP, which is thought to have been used in last week’s London attacks, is both hard to detect and made from a mix of common household chemicals.

A BBC report said evidence of acetone peroxide, the common name of triacetone-triperoxide (TATP), had been found at a home in Leeds, in the north of England, linked to one of the four London bombers.

It was the same type of explosive that Al Qaeda “shoe bomber” Richard Reid tried to detonate on a Miami-bound flight in December 2001, three months after the September 11 attacks in New York and Washington that killed some 3,000.

The development suggests that the explosives used in London were homemade, and not of military origin as had initially been thought.

Although the recipe for TATP is complex, its ingredients can be found in simple household goods: sulphuric acid — found in drain cleaner — hydrogen peroxide, and acetone, often a constituent of nail polish remover.

Once assembled and linked to a detonator, the mix is highly unstable and liable to blow up if exposed to heat or sudden movements.

Bomb-sniffing dogs do not always detect the substance although they can be trained to detect the residual acetone present in TATP.

Israeli researchers have also developed a device, the Peroxide Explosive Tester (PET), which they say can recognise TATP — the explosive used in the attack on the Dolphinarium nightclub in Jerusalem in 2001, which killed 21.

TATP has surfaced in a number of recent terrorism investigations.

A recipe for the explosive was found at the Brussels home of a Tunisian ex-footballer, Nizar Trabelsi, who was jailed in 2003 for his part in an Islamic militant plot to blow up a US airbase in Belgium.

The substance also figured in the inquiry surrounding Ahmed Ressam, an Algerian jailed for helping to plot an attack on Los Angeles airport in 2000, as well as the probe into a foiled attack on the eastern French city of Strasbourg in 2000.

“I would be surprised if (the London bombers) had used a military explosive: Islamic militants have always manufactured chemical explosives,” said a French counter-terrorism source. “They live in an isolated world... and these are products that can be bought on the high street,” he added.

He also said that ‘highly technical chemicals training existed in Pakistan, notably in camps in Kashmir”. —AFP