MI5 Security Service Threat Levels

Mi5 HQ in London

As we all know to our cost, terrorists do carry out attacks in the UK, sometimes with truly terrible results.

Whilst Wye Security cannot have a direct effect on the likelihood of an attack, we prize the safety of our customers and therefore thought it was a good idea to provide details of the current threat level (see the footer of all of our pages) as well as what they mean.

What the threat levels mean

Every threat level provides a broad indication of the likelihood of a terrorist attack in the UK.

  • LOW means an attack is highly unlikely
  • MODERATE means an attack is possible, but not likely
  • SUBSTANTIAL means an attack is likely
  • SEVERE means an attack is highly likely
  • CRITICAL means an attack is highly likely in the near future

How are these threat levels decided?

The threat level for the UK from international terrorism is set by the Joint Terrorism Analysis Centre (JTAC), using a variety of (secret) sources.

Also, MI5 is responsible for setting the threat level in Northern Ireland, these threats come from a different source.

The threat level is calculated using a variety of sources and factors:

These include:

  • Available intelligence. Only in rare instances can specific threat information be relied upon. More often, judgements are based on a wider range of information which can be fragmentary at best.
  • Terrorist capability. The abilities of all known terrorists and the methods they use, this often being based on previous attacks and from other intelligence inputs is also taken into account.
  • Terrorist intentions. The known aims of the terrorists and the ways they may achieve them, for instance, what sort of targets they might attack is also considered.
  • Timescale. The threat level also expresses the likelihood of an attack in the near future. Experience has shown that some attacks take years to plan, while others are put together very quickly, so a judgement call is always needed as to when the attack might occur.

What does this mean and how should you respond?

In reality, these Threat levels are for information only, the public only being told so that they are aware of the situation. However, this extra awareness can be useful as the police and MI5 rely to some degree on the ‘eyes on the ground’ that the public can naturally provide.

It must be remembered however that vigilance is vital regardless of the current national threat level, thus being especially important when the threat levels reach high levels.

So, if you have information about possible terrorist activity, call the Anti-Terrorist Hotline: 0800 789 321.

The Anti-Terrorist Hotline is for tip-offs and confidential information. For warnings about possible bombs or other urgent threats please call 999.

See https://www.mi5.gov.uk/threat-levels