Today's Green Alliance seminar on compostable plastics has left me with a bitter-sweet taste of the markets in my mouth.

The day started with presentations and discussions on the positive and negative points of using compostable plastics made from renewable carbon sources such as corn starch: collection methods, the supply chain and a cradle to cradle carbon analysis. Very informative but with no real concensus from the myriad of stakeholders present on the best course of action to their use in the future.

A representative from one of the leading private sector plastics manufacturers turned the entire day round for me, just before the close of play. His statement was simple: bioplastics need not be compostable. They can be made chemically identical to any plastics currently on the market and once significant investment is made to provide an economy of scale in terms of production, within a few years they will render petro-chemical plastics obsolete.

These bioplastics can be made using organics from the waste stream; the technology is proven and all that is needed now is the infrastructure to supply the manufacturers with feedstock. This will happen because it makes economic sense. The feedstocks are cheap and locally sourced and as geopolitcally sensitive as a cheese sandwich, or indeed anything else I didn't finish at the lunch they provided.

The vision is an almost fanastical one - a world where we can still recycle our plastic bottles in the same faciclites we do at the moment, it will still make economic sense to reduce consumption and plastics will contain no fossil carbon. The vision of the envirimnmental campaigners, their original and often economically unsound direct action has created a desire in the public conciousness for an ethical alternative to fossil plastics which the private sector has sought to exploit. Low and behold they have discovered that it can make real economic sense to take this route and the world looks set to change for the better.

Harness the markets!