Meanwhile, the former deputy-head of the UN mission in Afghanistan accused his former boss of suppressing evidence of fraud in the presidential election in August.

ECONOMIST: Politics this week

Mr Yates also said that "perhaps more could have been done" to investigate the allegations, which first surfaced in 2005, but rejected claims of deliberately suppressing evidence of wrongdoing by journalists and executives.

BBC: Culture, Media and Sport Committee

During the impeachment of Joseph Estrada, Mrs Arroyo's predecessor, his allies succeeded in suppressing critical evidence, causing the trial to collapse in rancour.

ECONOMIST: President Arroyo toughs it out