 At the moment in the United Kingdom, when we shop at supermarkets like this, we're currently using over 8 billion single-use carrier bags a year, which equates to approximately 60,000 tonnes of plastic or about 130 bags per person. Most single-use carrier bags, like this one here, are made out of fossil fuel-derived polyethylene and were subject to a five-pence levee in Scotland, Wales and Northern Ireland and in the near future England too. Here at the Open University, we're helping UK industry develop new biodegradable plastic carrier bags and packaging materials. When developing biodegradable plastics, our target is for materials to lose 90% of their carbon content within less than one year, whilst at the same time having no toxic properties. In our labs, we're working in partnership with DEFRA and a UK polymer company to undertake a series of biodegradability and ecotoxicology experiments and tests. To do this, we use instruments such as this respirometer, which measures the breakdown of plastic materials through the evolution of carbon dioxide. This setup is currently simulating idealised composting conditions. Within each of these vessels, we have a compost-type material and plastic carrier bag film cut up into tiny pieces so the two mediums can interact with one another. Because it's idealised, we have high temperatures and constant aeration through these inlet and outlet tubes here, which feed directly into our gas analysers. In this instance, measuring a high amount of CO2 from the compost and plastic mix indicates biological breakdown and are positive results. Today's carrier bags mainly end up in landfill sites, but many evade waste treatment and recycling processes altogether and end up littered all over the countryside, or perhaps more worryingly in the world's oceans. The world's oceans are currently estimated to contain over five trillion pieces of plastic. We'll put another way, about 270,000 tonnes. Here, plastics represent a threat to animals through entanglement, choking and poisoning. We expect the results from our experiments to come through within the next year and biodegradable carrier bags that we've helped develop come into stores within the next two years.