What Are The Differences Between the National Security Threat Levels?

image of an eye gathering intelligence on security threat across the world

Recently, and according to the BBC, the national security threat level was raised from ‘Substantial’ to ‘Severe’, which means that a terrorist attack on the UK is highly likely.


Why was the threat level raised in the UK?

While there is no specific intelligence of an imminent incident, the move from ‘substantial’ ‘severe’ was taken following the shooting in Vienna, in which four people died. As well as a knife attack that occurred in Nice, France the week before.

It is believed that the raising of the threat level was taken as a ‘precautionary measure following the horrific events of the last week in France and last night in Austria’, according to Priti Patel


What are the different threat levels?

MI5 have five different levels of threat, these are:

  • Low – means that an attack is highly unlikely
  • Moderate – means that an attack is possible, but not likely
  • Substantial – means that an attack is likely
  • Severe – means that an attack is highly likely
  • Critical – means that an attack is highly likely in the near future


How are threat levels decided?

The threat levels for the UK are set by the Joint Terrorism Analysis Centre (JTAC), part of MI5, and they are responsible for setting threat levels for both Northern Ireland and Great Britain. Before reaching a judgement on which threat level should be decided, there are several circumstance factors that need to be taken into consideration first.

Factors such as available intelligence, terrorist capability, terrorist intentions, and timescale.


Available intelligence

It is very rare that intelligence is available and can be relied upon, however, judgements about the threat can be based on information gathered from a wide range of places. This is fragmentary but can be achieved by looking at the current level and nature of the terrorist activity. Other available information to take a look at is comparing events in other countries and previous attacks.

Terrorist capabilities

This is a factor that takes into account the current capabilities of the terrorists in question, and the method that they may use, based on previous intelligence or attacks. This factor also looks at the potential scale of an attack.

Terrorist intentions

This consideration takes into account publicly available information and intelligence to examine the overall aims of the terrorists. As well as considering the ways they might attack and what they would consider attacking and targeting.


Threat levels don’t have an expiration date, they are subject to constant review to ensure that they remain current. If no specific intelligence is present, then a judgement about how close an attack may come to fruition is made. Judgements are made based upon past incidents; we know that some attacks take years to plan, while others are put together quickly.


Useful links


Contact Umbrella Security

If you would like any further information on security services delivered by Umbrella Security, or you would like a non-obligatory quote to protect your property, please contact our team today on 0121 554 2761 or fill out our online enquiry form.

Scroll to Top