MI5 terror threat warning level raised to 'critical'

The United Kingdom's Joint Terrorism Analysis Centre (JTAC), a division of the security agency MI5, has raised its threat level to critical. Critical denotes that a terrorist attack is expected imminently. The threat is noted as being from al-Qaida, groups associated with al-Qaida, and other Islamic extremists. The change was made as a result of an earlier incident where a burning jeep drove into Glasgow Airport, which has been linked to the attempted London car bombings of the previous day.

MI5 also indicated that, although the threat comes principally from al-Qaida and related networks, Northern Ireland-related terrorism remains a threat.

In a press release Saturday, Home Secretary Jacqui Smith said, "I can confirm that JTAC has raised the national threat level to critical. This is in response to the events of the last 48 hours. Critical is the highest level of threat, and the threat level will be closely reviewed on a regular basis. Appropriate security measures have been put in place."

A terror alert system was set up by the UK government to keep the public informed about the level of threat to the UK from terrorism. According to the Home Office, the likelihood of a terrorist attack taking place in the UK is identified in following threat levels:

critical - an attack is expected imminently

severe - an attack is highly likely

substantial - an attack is a strong possibility

moderate - an attack is possible but not likely

low - an attack is unlikely