Twin Towers

Tony Blair was warned there could be a UK terrorist attack " even more appalling" than 9/11, declassified government documents have revealed.

Days after the 2001 US attacks, the then Prime Minister was told of the dangers of weapons of Mass Destruction .

In The Letter , ex-defence minister Sir John Stanley said he was almost certain terrorists would get a " dirty" bomb.

The papers also reveal how Baroness Thatcher wrote to Mr Blair to praise his " resolve" following the attacks.

Nearly 3,000 people were killed in The Four attacks on the US on 11 September 2001. Hijackers had crashed two airliners into the Twin Towers of the World Trade Center, and a third hit The Pentagon , the headquarters of the US Department of Defense.

The Fourth plane crashed in Pennsylvania after a passenger revolt.

A few months after the 9/11 attacks, the newly released files reveal Mr Blair was warmly praised by a political opponent - ex-Conservative Prime Minister Margaret Thatcher .

" I greatly admire the resolve you are showing, " ran her handwritten note, dated April 2002. She Said Mr Blair had shown Britain was a " staunch defender of liberty" and " a loyal ally of America".

" That is the very best reputation Our Country can have, " she wrote, with The Words firmly underlined in her blue felt pen.

Other stories from The National Archives:

However, the papers reveal Mr Blair had earlier been given a stark warning about The Terrorist threat to the UK.

Writing privately to the Prime Minister in The Days after the 9/11 attacks, Tory MP Sir John Stanley said it " was not in the National Security interest" to put some of the points he wanted to raise in the Public Domain .

Sir John highlighted the 1995 Sarin attack on the Japanese underground, which had killed 12 people, and pointed out a 1998 Foreign Office Intelligence Assessment suggesting anthrax could kill millions in a British city.

It seemed " well nigh certain" that terrorist organisations would obtain a portable " dirty" Nuclear Device , he wrote, " if they have not done so already".

The 9/11 attacks prompted the then-Labour government to take immediate precautionary measures, boosting security at airports and government buildings. But Sir John Stanley believed there needed to be a more fundamental shift.

He urged the government to base security, civil defence, and intelligence policies on the assumption that " a terrorist WMD attack on one or more of the centres of population in the UK will be attempted, and attempted in the near and foreseeable future".

He Said more money should go into national intelligence, and civil defence should be rebuilt to deal with the consequences of a WMD attack. There should be provision of vaccines, and anti-radiation supplies to increase the chances of survival in case of a biological chemical or nuclear attack, he wrote.

Sir John said there must be far closer surveillance and easier detention of suspect terrorists in the UK, and the government should have powers to determine security measures for building in private as well as public ownership.

Iain Duncan Smith , who had just become Conservative Party leader, followed up his colleague's letter, saying The View " from such a source" should be taken " with great seriousness".

Mr Blair responded by saying he had commissioned reviews of anti-terrorist measures immediately after The Attack . He Said it would take time to develop and introduce new systems but they'd be brought in " as quickly as possible".

He Said The Greatest threat was still from conventional attacks, rather than WMD.

Behind The Scenes the government did take action. Many of the points raised by Sir John were addressed, though it's unclear if his particular intervention made an impact.

Sir David Omand was security and intelligence coordinator [Permanent Secretary] in the Cabinet Office from 2002 and established The Contest counter terrorism strategy.

Even before he arrived, Work was well under way to prevent WMD attacks, or deal with them if they took place. For example, equipment was being developed to detect radioactive material at UK entry points - Work which became known as " Operation Cyclamen".

Anti-viral drugs were stockpiled and decontamination vehicles procured. The Prevent Strategy was established to try to stop people supporting terrorism.

According to Sir David, The Emergency planning was often done quietly, because the government didn't want to " put people in fear".

Source of news: bbc.com