UPDATE 2-Poland's parliament speaker resigns over private flights scandal

(Adds analyst, further context)

By Marcin Goclowski and Alan Charlish

WARSAW, Aug 8 (Reuters) - Poland's parliament speaker said on Thursday he would resign after it was revealed that he used government aircraft for private trips, suggesting the ruling nationalists aimed to defuse a scandal that could affect their re-election campaign.

With elections set for October, the affair has embarrassed the right-wing Law and Justice (PiS) party, which has said it is cleaning up an alleged legacy of corruption and communist influence tolerated by previous governments.

"I plan to submit my resignation tomorrow," Marek Kuchcinski told a news conference alongside PiS leader Jaroslaw Kaczynski, three days after the speaker apologised for using a government Gulfstream jet for 23 flights with his family.

"We believe that given we are building very high standards in public life, conclusions must be drawn and above all we need to listen to public opinion," said Kaczynski, who has no formal government post but is seen as Poland's most powerful figure.

A poll published by Super Express tabloid on Thursday showed that almost two-third of Poles wanted Kuchcinski gone. Local media speculated that his deputy Ryszard Terlecki, another senior PiS politician, will take over as speaker.

Political analysts said that until Thursday the PiS had adopted a wait-and-see approach on Kuchcinski, hoping the scandal would die off amidst the summer holiday lull.

But after further media revelations of flights on government aircraft by his relatives and discrepancies in explanations by Kuchcinski and the government, the potential damage became too serious to gloss over.

"There was a threat of an erosion of voters who have joined PiS only recently and a risk that PiS could lose its absolute majority in parliament, hence the decision to let the speaker go," said Warsaw University political scientist Rafal Chwedoruk.

He cited a spate of negative memes on the Internet about "frequent-flyer" Kuchcinski, showing him walking a dog using a helicopter or stuck at work until late and irritably telling his wife by phone: "Where am I? On a plane, of course."

The PiS has clung to a clear lead in recent opinion polls, driven by robust economic growth, a generous social spending programme and its championing of traditional conservative values. That combination has helped the PiS avoid serious political damage despite several financial scandals.

A survey taken by IBRiS pollster before the speaker scandal broke gave PiS 41.7% if elections were held now, with the main opposition bloc, the centrist Civic Platform, at 25% and a group of leftist parties at 10.2%. (Reporting by Marcin Goclowski and Alan Charlish Editing by Mark Heinrich)