UPDATE 1-After leak worries, UK stats chief stops economic data previews for officials

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LONDON, June 15 (Reuters) - Britain's statistics chief said on Thursday he will stop giving government officials early access to sensitive economic figures ahead of publication, a move that follows concern about possible abuse of market-sensitive data.

The change will be effective from July 1, John Pullinger, Britain's national statistician, said.

In March, Reuters published a report showing movements in the value of British sterling against the U.S. dollar often followed an unusual pattern before monthly releases of official retail sales data.

The Wall Street Journal published an analysis which showed similar movements in British government bond futures ahead of data releases.

Pullinger said he had become increasingly concerned about growing access to economic statistics by government officials and that he tightened Office for National Statistics' procedures in March as a result.

"It is already clear to me that the changes are not successfully dealing with the risks the review sought to mitigate," Pullinger said in a letter to the UK Statistics Authority watchdog, published on Thursday.

"I have therefore decided that pre-release access to ONS statistics will stop with effect from 1 July 2017."

The statistics authority welcomed the move.

"Equality of access to official statistics is a fundamental principle of statistical good practice, and the existence of pre-release access undermines trust in our official statistics system," said David Norgrove, chair of the UK Statistics Authority.

Earlier on Thursday, sterling weakened against the dollar before the release of worse-than-expected retail sales numbers - a move that fit with the trend observed in the Reuters analysis published in March.

In March, the chair of parliament's Treasury Committee urged Britain's Financial Conduct Authority, which tackles financial market abuse, to investigate the media reports about unusual movements in financial markets ahead of official data releases.

Foreign exchange traders regularly post messages on Twitter saying they believe data is leaked ahead of publication, based on movements in the pound.

(Editing by William Schomberg/Jeremy Gaunt)