Bulgaria protesters struggle to unite for election challenge

* No sign they can form party in time for May election

* Will make it easier to form new government

* But means Bulgarians' discontent may persist

By Angel Krasimirov

SOFIA, March 11 (Reuters) - Leaders of protests that felled the Bulgarian government are struggling to unite to form a single political party that can challenge the old order at May's election.

Despite hundreds of thousands of people protesting in the past months over what they see as a corrupt political class that has failed to improve living standards, that impetus is now waning and their leaders are squabbling among themselves.

"Suddenly, every Bulgarian is ... the organiser of the protests," Angel Slavchev, from the National Citizens Initiative, one of several groups competing to lead protesters, told Reuters. "I have had enough of fakes."

With no unified protest movement standing, the vote is again likely to be divided between the two largest parties - outgoing Prime Minister Boiko Borisov's rightist GERB and the Socialists - and two or three smaller groups.

Opinion polls suggest no party will win a majority, but the lack of a new grouping will make it easier to stitch together a coalition - averting fears that a second election would have to be held, which would raise questions over the implementation of economic policies needed to maintain a currency peg to the euro.

But the lack of representation in parliament is likely to mean the discontent of the hardcore of protesters in the poorest European Union will persist, threatening turnout in May and perhaps further weakening the mandate of the new government.

"We can expect that people ... will just not vote and we will have a low turnout if the protest leaders fail to form a party," said Kancho Stoichev, an analyst with pollster Gallup. "The rest of the voters will just go and vote for the established parties."

Protest organisers had hoped to attract large crowds on Sunday to maintain momentum after Borisov cut electricity prices and then resigned last month, but numbers fell sharply from previous weeks.

President Rosen Plevnevliev, who will appoint an interim government on Tuesday to lead the country until the election, has sought to dampen anger by holding talks with protest leaders.

But his plan for a 35-member public council to advise the interim government collapsed after representatives of protesters objected to the inclusion of some wealthy businessmen.

Many protesters say the elite maintain a corrupt system formed after the 1989 collapse of communism and focus on their own interests rather than helping people living on an average wage of 400 euros ($520) and pension less than half that.

Despite their common cause, the groups have nonetheless failed to coalesce around a figurehead.

"All of them are talking about unity but nobody has seen it," Yanaki Ganchev, who leads another protest group, said at a tent camp set up outside Bulgaria's parliament. ($1 = 0.7703 euros) (Editing by Alison Williams)