‘Chemical bomb’ shows terrorists are getting more sophisticated
Security experts warn that specialist skills needed to make 7/7-style device suggest creator is still free
THE first terrorist bomb attack in Britain since 2005 represents a hugely worrying step change in the tactics of the jihadists, security experts said last night.
Salman Abedi is believed to have detonated a chemical bomb packed with deadly shrapnel, similar to those used by the suicide bombers in the 7/7 attacks on London.
Recent attacks in the UK, including the murder of Drummer Lee Rigby and the attack on Westminster in March, were relatively simple, involving vehicles and knives, and required little planning or coordination.
But terror experts said the use of a complex and difficult-to-manufacture bomb suggested terrorists were increasing the sophistication involved in their attacks.
David Videcette, a former Scotland Yard counter-terror officer, who helped to investigate the 7/7 attacks, said: “From what we have seen so far it suggests that the device was a fairly similar size to the ones used in the London Tube bombings.
“It sounds likely to have been a device carried in a bag containing a tub with chemicals and then surrounded by nuts, bolts and nails to cause the maximum amount of damage.
“Such devices are extremely difficult to get right. They need an initiator, such as a battery, which sends a charge to a detonator, which then sets off the main charge.
“Getting all that to work in the right order and at the right time is very technical. The skills needed are not something that can be acquired easily and I would think it is highly unlikely that the suicide bomber is the bomb maker.”
He added: “This represents a massive step change in terms of attack planning over the last 10 years.”
Mr Videcette said in order to find out whether there was a wider network of terrorists behind the attack, police and security services would be examining who Abedi had been in contact with in recent weeks and months.
He said: “The authorities will be looking at what intelligence they hold on this person, both in terms of the security services and the police. They will be looking at gathering any information on who he has been in contact with and who he has associated with.
“However, the terrorists are very aware of the techniques the police use and so as they become more professional, they try to avoid attention by stopping using their mobile phones or computers, which may make things difficult for investigators.”
Will Geddes, a security expert, said: “If the suicide bomber has been given the device by someone else, that opens the possibility that there is still a bomb maker out there somewhere and finding him will obviously be the top priority for the police and security services.”
There will also be questions for the security services about how a bomb maker managed to assemble the materials for the device without his behaviour alerting the authorities.
If the device was a chemical bomb, it would have used a large amount of hydrogen peroxide. Anyone purchasing large quantities of such materials online or in shops would run the risk of being flagged up to the authorities.
In recent years terrorists have turned to the chemical pentaerythritol tetranitrate (PETN), the major ingredient in Semtex, as the favourite bombmaking ingredient.
It is one of the most powerful explosives and is popular with terrorists because it is difficult to detect and is relatively stable. In 2001 Richard Reid, the shoe bomber, tried to blow up a transatlantic airline using a device packed with PETN.
But the chemical is difficult to get hold of and supplies and sources are monitored by the security services.
In the past plots have been interrupted when would-be terrorists have discussed obtaining materials.