A Mercyful Fate compilation is in the works and the Danish frontman reveals that enhancing selected tracks using modern studio techniques has breathed new life into the recordings.

He tells Canada's The Metal Voice: "I don't like the versions which are out - I think they have been crushed to death and a lot of the original sounds have been squashed.

"One of the main reasons to remaster was to get the songs better presented on radio. But when you make them just louder - you just compress them and lose so many of the details. You crush them to death and I think there's so much missing. There was the opportunity to do something great - so we enhanced what we could find of the old stuff."