Ireland’s debt management agency said it felt compelled to criticise Standard & Poor’s rationale for downgrading the country’s long-term rating by one notch to AA-.

“Exceptionally, we have taken issue with the rating agency. It’s something we don’t like to do but there comes a point when the analysis is not robust,” John Corrigan, the chief executive of the National Treasury Management Agency (NTMA), told state broadcaster RTE.

“While the downgrade is disappointing given the negative flow of news since 2009 it’s hardly surprising.”