The UK terrorism threat level is expected to be lowered from "severe general" to "substantial", say security sources.
The threat level has moved from "severe general" to "substantial"
Intelligence analysts in the UK reviewed the terror alert every day.
BBC security correspondent Frank Gardner said analysts had recently cut the threat level for Irish terrorism.
They were expected to do the same for international terrorism imminently but said threat to UK interests remained real and serious.
The government refuses to discuss the issue publicly. The Conservatives say threat levels should be publicised.
The expected change in terror alert comes after alleged terror plots were foiled but security measures by the police and intelligence agencies will continue as before.
Conservative homeland security spokesman Patrick Mercer told BBC News people should be told about the changing threat levels.
He asked: "Why haven't we got a single minister for homeland security that can say look, people, actually things are a lot better so without taking your eye off the ball you can perhaps ease things off a little bit?"
He said the UK had been at a higher state alert than the US since November 2003.
"Intelligence was received in November 2003 to suggest that there was likely to be an attack across the UK somewhere, that a real plot was being hatched," he told BBC News.
"Since then, we have seen some very successful arrests by the security services and, as a result, I believe it will be reduced in the next day or so to 'substantial', which means that there's still a threat but where it is coming from and against whom it is targeted is not known."