Blunkett blunders in issuing dire warning of 'dirty bombs'

"Dirty" nuclear bombs, poison gas and "suicide" boats, trains and planes could all be used by al-Qa'ida terrorists against Britain, David Blunkett, the Home Secretary, admitted yesterday.

The warnings were contained in Mr Blunkett's foreword to a new counter-terror assessment published by the Home Office in an attempt to encourage greater vigilance, which was later rewritten to moderate its impact.

However, the Home Secretary's references to explicit threats were withdrawn within an hour of being issued as officials worried about their impact on the public. An administrative error was blamed for the erroneous release of what was described as "a first draft" of the document.

A Home Office spokesman said that the contents of the original document were still valid but the Government wanted to focus not on "specific" threats but the more general threat posed by terrorism.

The paper, titled "Counter Terrorist Action since September 2001", summarises progress made over the past 14 months, including action taken in recent weeks to detain suspects under new legislation, to extend the list of proscribed organisations, to combat the financing of terrorism and to improve security at airports.

In his foreword to the paper, Mr Blunkett warns that "there is no such thing as 100 per cent intelligence" and that "British citizens remain at risk from both international and Irish terrorists. We cannot be sure of when or where or how terrorists will strike. But we can be sure that they will try. They may attempt to use more familiar terrorist methods such as leaving parcel or vehicle bombs in public places, or hijacking passenger aircraft," he wrote.

"However, they may try something different, perhaps as surprising as the attacks on the World Trade Centre, or the theatre seige in Moscow. Maybe they will try to develop a so-called dirty bomb, or some kind of poison gas. Maybe they will try to use boats or trains rather than planes. The bottom line is that we simply cannot be sure."

Mr Blunkett went on to stress that no attack was "imminent". "But it does mean that we must all ... make security a part of our everyday lives," he added.

Since 11 September, ministers have been careful not to scare the public with warnings of specific threats included in intelligence reports. Revealing the possibility of a nuclear bomb or the use of boats and trains is sure to upset some within Downing Street.

The Home Secretary also called on the public to be extra vigilant in the run-up to Christmas, and warned that terrorists may use parcel bombs. He said people should be particularly careful at airports and train stations, and report anything suspicious to the police.

In his original text, Mr Blunkett described the threat from al-Qa'ida as real and serious, and added that he was sure the terrorist network would attempt to kill British citizens.

In the later document, the Home Secretary summarised the precautions taken by the Government since the 11 September attacks, including extra security at airports, but did not provide any detailed or new information about specific threats. He wrote: "The kind of risk that the UK is used to because of our experience with terrorism related to Northern Ireland – car bombs and parcel bomb in public places, assassinations for example – must be taken seriously, and the public must remain vigilant."

The publication of the document coincided with yesterday's meeting between Mr Blunkett and Governor Tom Ridge, the head of US Homeland Security, to discuss measures being taken by both governments to protect the public from global terrorism. Tony Blair also met Mr Ridge last night at Downing Street.

Governor Ridge is also holding talks with Sir David Omand, the Government's recently appointed Security and Intelligence Co-ordinator.