The Minister will no doubt also wish to explore the distance travelled and the waste and air pollution caused by carting around empty bottles so that they can be refilled. I am not against his ideas on the recycling of bottles; that is just one step.
I draw the Minister's attention to the challenge of volume. An immediate and easy solution is not essential, but it would not be impossible to measure the volume twice, first uncompacted and then after the waste has been compressed. We could have two measurements, or even three. The Minister can take this as far as he needs to. If we measured on weight alone, we would send out very different signals. I remember the Minister's comment about the wheelie bin; the volume of the bin was the problem because it was too large.
Plastic bottles can be a problem. A drinks company in my constituency produces huge numbers of bottles, which it fills with water and soft drinks. It is not necessarily wrong to produce plastic bottles; but if we are going to address the waste problem, we must be more innovative about how we measure the volume. We need to prevent them from ending up in landfill.