The restaurant on Kingston high street was founded in 1989 and overlooks the River Thames. It offers a full menu of vegetarian dishes from around the world alongside a seasonal, daily special menu.
The venue best Mildreds in Soho and fast-food restaurant Karma-Free Pizza in the poll of best of the capital's growing number of meat-free eateries. Members of the public voted on 32 restaurants with the highest scoring then judged by a panel of experts, including a representative of the Sustainable Restaurant Association (SRA) and chef Arthur Potts-Dawson, until a winner was found.
Criteria for the competition included commitment to vegetarianism and sustainability, provenance, sustainability of water, waste practices and community engagement.
Potts-Dawson said: "Riverside edged it over the other entrants with excellent ethical credentials, in terms of its community activity. Food enterprises have to be supported by the community. That’s the future for food outlets in big cities. Without that they won’t survive. Practices in the restaurant are obviously based on a strong lifestyle belief system, which is probably the only way to get your business to ring true in terms of ethics. What Riverside is doing culturally makes a big statement."