LONDON (Reuters) - With just days to go before Britain's June 23 referendum on European Union membership, Britain's newspapers have publicly come out on their chosen sides, hoping to influence the debate as polls paint a picture of an evenly split electorate.

PRO-REMAIN NEWSPAPERS

THE TIMES

Britain's Times newspaper has come out in support of remaining in the EU, with its Saturday June 18 issue bearing a leading article entitled "Why Remain is best for Britain".

"On balance we believe Britain would be better off leading a renewed drive for reform within the EU rather than starting afresh outside it," the newspaper said.

That put the Rupert Murdoch-owned Times at odds with two other newspapers in the media tycoon's stable. The Sun and The Sunday Times have both thrown their weight behind Brexit.

THE MAIL ON SUNDAY

Britain's right-leaning Mail on Sunday newspaper has endorsed the campaign to remain in the EU, saying Britain would be safer, freer and more prosperous in the bloc.

"For modern Great Britain to thrive and prosper we must work with, not against, our European partners; we must keep our seat at Europe's top table and help shape its destiny; our strong, clear voice must be heard inside Europe, not be shouted from the sidelines," the newspaper said.

THE OBSERVER

The Observer newspaper, part of the left-leaning Guardian Media Group, told its readers to vote to stay in the EU. The paper said the EU was not perfect, but that overall it had been a force for good.

"Remaining in the EU will not magically eliminate the challenges Britain faces in the years to come. But if we choose to do so, it will keep Britain at the heart of reforming the European project so that the nations of Europe are together better equipped to face them," The Observer said.

THE GUARDIAN

Britain's main left-of-center newspaper backed Britain remaining in the European Union, telling its readers that they should "keep connected and inclusive, not angry and isolated".

"Vote for a united country that reaches out to the world, and vote against a divided nation that turns inwards. Vote to remain," the paper said.

PRO-LEAVE NEWSPAPERS

THE SUN

The Sun, the nation's biggest-selling paper, urged its readers to vote leave on its front page on June 14.

"We must set ourselves free from dictatorial Brussels," said the tabloid, which has a circulation of 1.7 million.

Many of its readers already back a Brexit according to polls.

THE SUNDAY TIMES

The newspaper urged its readers to vote to leave the EU as a way to press for deeper reform of the bloc, which might make it more acceptable for Britain to actually remain in.

"Yes, we must be prepared for a bumpy ride, but we should hold our nerve. This vote may be the only opportunity we shall ever have to call a halt to the onward march of the centralizing European project," the newspaper said in an editorial.

THE SUNDAY TELEGRAPH

The conservative newspaper urged its readers to vote to leave, arguing that the EU belongs to the past and by leaving it Britain would be able to decide who should come to work in the country.

"Once we have left and are no longer subject to the free movement of labor, popular worries about immigration will become a matter for the British government and for parliament," the paper said.

(Reporting by Sarah Young and Costas Pitas; Editing by Ros Russell)