The rule of Chen Shui-bian, Taiwan’s president, was plunged into uncertainty on Friday as prosecutors charged his wife with corruption and said they had evidence that he had abused his office for financial gain.

The Taiwan High Court Prosecutors’ Office indicted Wu Shu-chen, the first lady, on charges of corruption, perjury and forgery. It said she and Mr Chen had “jointly used the opportunities provided by [his] office to swindle” T$14.8m ($450,000) from a discretionary presidential budget for secret diplomacy and other purposes.