FACTBOX-Ukraine's parliament dissolved - what next?

(Reuters) - Ukrainian President Viktor Yushchenko's decree to dissolve parliament came into force on Tuesday, a move his arch rival Viktor Yanukovich said would threaten stability.

Under the constitution, parliament continues to work until a new chamber is elected. The new election is set for May 27.

Here are the main winners and losers, and likely scenarios as to what could happen next.

WINNERS:

** Opposition leader Yulia Tymoshenko, fired as prime minister in 2005 after eight months in office. She had hoped to return to her job after her party finished second in a March 2006 election but attempts with "Orange Revolution" allies to build a coalition collapsed. The main proponent of dissolution, her poll ratings are on the rise. She might fare even better in an early election and be restored to the prime minister's job.

**Yushchenko. His personal poll ratings and those of his Our Ukraine party remain poor. But the decision to dissolve parliament returned pro-Western Yushchenko to a key controlling position in Ukrainian politics. He is likely to receive a friendlier parliament after the poll.

LOSERS:

** Viktor Yanukovich and his Regions Party. Humiliated in the Orange Revolution, they staged a comeback in a parliamentary election in March, finishing a strong first. Pro-Russian Yanukovich was appointed prime minister in August 2006 and systematically secured control over the economy and key government jobs.

While his party remains at the top of opinion polls, considerable control over its activity is exerted by Rinat Akhmetov, Ukraine's richest businessman, who has no interest in any long-term political turmoil.