An alleged plot to release poisonous gas on London's underground rail network has raised widespread concern over the possibility of such a terrorist attack. On Monday, the UK government's Chief Medical Officer announced a poster campaign to tell passengers what to do in the event of a gas attack.

On Sunday it was revealed that three men had been charged under the UK's Terrorism 2000 Act following raids on houses in north London on 9 November.

No chemical weapons were found during the raids but the three men were remanded in custody on Monday for possessing "articles for the preparation, instigation and commission of terrorist acts". Reports suggest this refers to forged identification documents.

The British intelligence service MI5 is reported by newspapers to have evidence that the men were involved in a plot to release a deadly chemical agent on London's underground system, which is used by three million commuters each day. The men are also alleged to have links with the Al-Qaeda terrorist network.

However, neither the UK government nor the police have confirmed that there is any evidence that the men planned to attack the underground system. The solicitor representing one of the three men accused the UK press of unfairly reporting the case.

Video evidence

Governments around the world have been warning their citizens of possible terrorist attacks, and the arrests have focused attention on what is already known.

Al-Qaeda's interest in preparing a variety of chemical weapons has been revealed in documents and manuals recovered in Afghanistan.

"Cyanide has surfaced a number of times surrounding Al-Qaeda's chemical program," says Magnus Ranstorp, an expert in international terrorism at the University of Saint Andrews in Scotland. Videotapes obtained by CNN in August show a chemical agent, thought to be cyanide, being tested on dogs at a training camp in Afghanistan.

Tube test

It is also known that a biological weapon attack on the London Underground would have terrible consequences. In February 2002, documents released from the UK's public record office revealed that the Ministry of Defence simulated biological attacks on the underground in the early 1960s, during the height of the cold war.

Scientists from the Ministry's Porton Down chemical and biological weapons research department mixed harmless spores of the anthrax analogue Bacillus globigii with talcum powder. They then released them on the Northern Line to test the dispersion of biological agents. They found that the spores spread to every one of the several dozen stations on that line.

The documents should have been made public in 1995 but were suppressed after the Aum Shinrikyo cult launched a gas attack on the Tokyo underground system in Japan in the same year. Sarin gas was released on trains killing 12 people and injuring thousands more.

On Monday, London Underground refused to comment on the counter measures currently in place but a spokeswoman said: "We are always speaking to police and reviewing what we can do."
 
SOURCE: NewScientist.com on the 18th November 2002