The government has criticised a BBC programme dramatising a terrorist attack on London as "alarmist and irresponsible".
The programme dramatises bomb attacks on the London Underground
Sunday's Panorama features a fictional account of how authorities cope with bomb attacks on the underground system and an exploded chemical tanker.
It also has interviews with London Underground staff saying they have not had training to deal with an attack.
Programme-makers claim it highlights "basic problems" in emergency planning.
In the show, set just into the future, a series of mock news reports detail how London is thrown into chaos after simultaneous bomb blasts on the Tube's Piccadilly, Central and Victoria lines and the explosion of a chemical tanker.
A panel of intelligence, emergency planning, police, fire, government and media management specialists examine the plans currently in place to cope with a major atrocity.
Problems highlighted include that police, fire and ambulance radios do not work underground and that the siren network used to alert the public has been dismantled.
Home Secretary David Blunkett declined to take part in the show, and condemned it as unnecessarily alarmist.
"We are disappointed to learn that the BBC appears to have adopted an irresponsible and alarmist approach over what is understandably an emotive and frightening subject for the public," a Home Office spokesman told BBC News Online.
He said the programme depicted a situation that was "simply not realistic".
"It is because of the approach taken by the programme that the government and emergency services declined to cooperate in its making."
The government's policy was to invest heavily in the prevention of terrorist attacks, he said, an example being the recent massive expansion of MI5.
"The government is committed to ensuring the public is alert but not alarmed by the threat by international terror."
Panorama says it has a public duty to highlight potential flaws in Britain's ability to deal with a terrorist atrocity.
The controversy comes a day after the Police Federation said they needed more money to train officers to respond to a chemical, biological, radiological or nuclear attack.
Terror Expert Professor Paul Wilkinson said a great deal had been achieved since the terror attacks of 11 September 2001, but agreed there was still a lot more planning that needed to be done.
London under attack will be broadcast on BBC One on Sunday, 16 May 2004 at 2215 BST