Ms Smith wants the paper to go into more detail than ever before about how the authorities are seeking to prevent atrocities from happening and respond to attacks which take place, said a spokesman.

It will reflect security services' judgment that the most serious terror threat to the UK continues to come from international groups linked to or influenced by Osama bin Laden's al Qaida network.

Experts have spent a year preparing the document, known as Contest Two, to take into account lessons learnt from recent terror outrages such as the attacks on hotels in Mumbai last year.

The new paper, to be published on Tuesday, will update the Contest strategy developed by the Home Office in 2003 and detailed in the Countering International Terrorism document in 2006.

For the last six years, the strategy has been divided into four strands - Prevent, Pursue, Protect and Prepare - to tackle all aspects of the threat from preventing radicalisation of potential terror recruits to disrupting terror operations, reducing the vulnerability of the UK and UK interests overseas and ensuring the country is ready for the consequences of any attack.

The Home Office spokesman said the new paper would take account of the way the terror threat has evolved and how the authorities are learning lessons from events.

The terrorism threat level, set by the Joint Terrorism Analysis Centre, has since July 2007 been "severe", which means that future terrorist attacks are highly likely but not thought to be imminent.

By 2011, Britain will be spending £3.5 billion a year on counter-terrorism. The number of police deployed on counter-terror work has risen since 2003 from 1,700 to 3,000, while the security service MI5 has doubled in size over the same period.

Between 2001 and 2008, almost 200 people have been convicted of terror-related offences.