Found this on the Digital Spy Forums, may not be true, hasn't been comfirmed:
Den Watts will be killed off from Eastenders in spectacular fashion after an amazing fall from grace.
The self proclaimed King of Walford, played by actor Leslie Grantham, will become more and more withdrawn after his daughters Sharon and Vicki leave and eventually will have a massive breakdown which will culminate in him holding family and friends at gunpoint in his beloved pub, the Queen Vic.
According to Eastenders producers, the scenes, will be the centrepiece of the BBC1 Soap's 20th Anniversary celebrations, will be amongst the most dramatic ever seen on British Television.
Actor Grantham was involved in a drama of his own last June when it was revealed in a tabloid that he had exposed himself on the internet in his dressing room. Several believed it would only be a matter of time before he would be axed and that's exactly what happened when new Executive Producer Kathleen Hutchinson took over.
57 year old Den also gets his son Dennis' 20 year old girlfriend Zoe Slater pregnant in order to continue a lie that keeps Dennis and his true love, half sister Sharon apart.
In his last scenes in the BBC Soap Den will terrorise several popular characters including Ian Beale, Pauline Fowler, Dot Branning, Jim Branning, Pat Evans, Sam Mitchell and Alfie Moon.
After gagging and bounding his fellow Walford residents Den goes on a maniacal rant before deciding to end it all. He turn on the gas cooker upstairs and starts a fire down in the bar. In a matter of minutes the whole building is engulfed in a massive fireball which takes not only it's evil landlord but also at least one more resident as well. The identity of the unfortunate 2nd victim will be a closely guarded secret up until the episode is shown.
So? I don't know if this could happen, but could get EE back on track in dramatic fashion!