LONDON, Jan.9: The UK government on Tuesday decided to keep the general public updated through regular e-mails on the prospect of an imminent terrorist attack.

From Tuesday night, the MI5’s website will provide a free registration service for those wanting the latest information about the threat level.

Subscribers entering their email address will receive a message with the words “MI5 news update” whenever there is a change on the website.

This could include a warning that the threat of an attack is higher or lower, though given the number of alleged plots under investigation, the level is unlikely to fall for many years.

The current level, as assessed by the Joint Terrorism Analysis Centre based at MI5’s London headquarters, is severe.

This is the second highest point on the five-grade system and means that an attack is highly likely but there is no specific information.

It has remained at severe since the bombings in London in July 2005 apart from a few days last August when the threat level rose to critical-- the highest--amid fears of an imminent attack on trans-Atlantic airliners.

The government and MI5 were previously sceptical about putting the threat levels into the public domain because they did not tell anyone what to do with the information.

There were fears that they could cause panic without helping to stop an attack.

But ministers were persuaded that greater transparency was preferable and the threat levels have been publicly available on MI5’s website since last August.

“After the events of last summer there was a lot of feedback from the public that the visibility of the threat level was useful to people,” said a Whitehall source.

“The threat levels are already published on the MI5 website but this is a way of making the details available more quickly.

“There is also plenty of security advice on the website telling people what they can do to protect themselves.”

People registering on the website will also be able to obtain instant updates when speeches or other information details are posted on the site.