How to unlock Underworld

Hi,

I understand this is a bit of a newbie question, but I have now cleared Battlefield on Madness level (though not all at 3 skull proficiency) and the first mission in Underworld, Road to Ruin is locked.

How do I unlock it, or when will it unlock? I am level 29.

Many thanks

Nniol

That's strange. I had Underworld Normal unlocked once I finished Battlefield Normal. AFAIK completing Battlefield Hard only unlocks Battlefield Madness, and Battlefield Madness doesn't unlock anything.
Which difficulty level of Underworld are you referring to anyway? Plain old Normal?

Though by the time I played A Matter of Life and Death Normal I had everything else in Battlefield Normal 3 skulled.

I've had the same problem, until I found out that after defeating the final boss, you actually have to do 1 more story bit until the next world unlocks. Good luck!