Northern Ireland terrorism threat level rises

The terrorism threat level in Northern Ireland has been raised from substantial to severe, meaning an attack is highly likely.

The move, based on an MI5 intelligence assessment, follows a rise in dissident republican activity, including a recent gun attack on a top police officer. It reverses a downgrade in Northern Ireland's terror threat level last March - its first change for 12 years.

It was announced by Northern Ireland Secretary Chris Heaton-Harris. MI5, the UK's Security Service, is believed to review the threat level every six months. The terrorism threat level remains substantial in the rest of the UK, meaning an attack is a strong possibility.

Threat levels are designed to give an indication of the likelihood of a terrorist attack and there are five rankings ranging from low to critical. Severe is one level below critical, meaning an attack is expected imminently.