In June last year, Khoeun Virath was elected as a commune councilor in Phnom Penh, the Cambodian capital, but months later his political party was banned and most of its leadership fled into exile — so now he works as a tuk-tuk driver to make ends meet.

Virath's story is just one example of how a once-thriving opposition has been silenced and pushed underground by long-serving Prime Minister Hun Sen and his allies ahead of a general election set for Sunday.

The government denies it has set out to sideline critics.