This week, low carbon taxi firm greentomatocars has parked up in the You ask, they answer spotlight. Established in 2006, it was the first taxi company in London to exclusively use Prius hybrids, and has since gone on to win an Energy Saving Trust "Fleet Hero" award and expand to Australia.

From Monday to Friday, the company will be online doing its best to answer your questions. Want to know more about its policy on carbon offsetting its journeys? How far its environmental efforts go? Or interested in how it compares to other "eco taxi" outfits, such as ecoigo and climatecars?

Just post your questions in the comments below to get things started.

Tom Pakenham, the company's chief executive, says his team will do its best to respond quickly but has asked me to note that greentomatocars is a small company and there may be a time lag between questions and answers.