DUBLIN, May 23 (Reuters) - The former chairman of the failed Anglo Irish Bank was acquitted on Tuesday on charges of misleading auditors about personal loans worth tens of millions of euros following a ruling by the judge, Ireland's Courts Service said.

Sean FitzPatrick went on trial last year accused of "artificially reducing" loans worth tens of millions of euros for a few weeks around the end of the company's financial year to avoid their full value being shown in annual accounts.

FitzPatrick pleaded not guilty to all 27 charges, including providing misleading, false or deceptive statements to auditors Ernst & Young (EY) and furnishing false information.

Judge John Aylmer ruled that the investigation carried out by Ireland's Office of the Director of Corporate Enforcement (ODCE) fell short of the impartial, unbiased inquiry to which an accused is entitled, national broadcaster RTE said.

Aylmer said key witnesses had been coached and the ODCE had failed to seek out evidence of innocence as well as guilt, according to RTE.

Anglo Irish, which was nationalised in 2009 and wound down in 2011, was synonymous with the casino-style lending practices that drove the "Celtic Tiger" boom and subsequent bust, pushing the Irish state into an international bailout in 2010.

Two Anglo Irish executives were among three Irish bankers jailed last year for between 24 and 42 months for conspiring to defraud investors. They were the first senior bank executives to be jailed in relation to the crisis.

FitzPatrick was also found innocent in 2014 on charges of illegal lending and providing unlawful assistance to investors.

(Reporting by Conor Humphries and Padraic Halpin; editing by Mark Heinrich) ((padraic.halpin@thomsonreuters.com; +353 1 500 1529; Reuters Messaging: padraic.halpin.thomsonreuters.com@reuters.net))