The majority of pubs are owned by big corporations that screw every ounce of profit out of their 'tied' houses, so called because the publican is tied to the company. So go for a free house, which is independent of a corporate body, owned by one of the smaller breweries or by Wetherspoons, who were the first to go smoke free and have been keen purveyors of Cuban Rum. Two big ethical points.
With the smoking ban, many pubs have put hugely wasteful CO2 burning patio heaters in the garden; any aspiring ethical publican would ban these too. There are a number of organic pubs, such as the Duke of Cambridge in Islington, that have been certified by the Soil Association, and a number of breweries that offer organic beers. My favourite is Whitstable ale from Shepherd Neame, although the organic hops come from New Zealand. It is suitable for vegetarians because bizarrely a lot of beer uses fish scales during production. Local pub grub with reduced carbon miles would also be an improvement.
The Boycott Bacardi campaign means that you need to find an establishment that produces mojitos with Cuban rum, organic mint and fair trade limes.
The Workers Beer Company has a pub called the Bread and Roses in Clapham, where pub staff are covered by a model union agreement negotiated with the T&G and perhaps the best wage rate in the country.
Home brewing may sound dodgy but one of the best pints I ever had was stout grown by my friend in a flat along Brick Lane.
The Campaign for Real Ale educates people about the virtues of real rather than tasteless cask beer. We must campaign to stop community pubs closing and stand up for small breweries under threat from the multinationals.