Berlusconi's mounting woes fuel talk of early vote

* Divorce filing adds to Italy PM's political, legal woes

* Berlusconi newspaper sees "plot" to oust him

* Key ally warns against early polls

By Gavin Jones

ROME, Nov 15 (Reuters) - Silvio Berlusconi's personal, political and legal problems are mounting, leading the Italian prime minister's media and political allies to speak of a plot against him and a risk of early elections.

"Berlusconi under siege," was the headline in Sunday's edition of Il Giornale, owned by Berlusconi's brother, over an article which promised to "reveal the plot" against him.

The tycoon leader has been under pressure since May when his wife announced she wanted a divorce and a series of sex scandals began to emerge.

But problems have been mounting of late rather than easing, leading many commentators to predict an early end to his 18-month-old government even though his approval ratings remain relatively high and he has an ample parliamentary majority.