Now here is an idea ...

The inventors of these who call themselves Greenbottle explain:

A cardboard outer that is made from pulped recycled cardboard – using egg carton technology.

A loose liner which prevents the milk from contaminating the cardboard and vice versa.

Once the bottle is used, the liner is removed and the bag can be disposed of in the general rubbish.

The cardboard can be put in either the cardboard recycling or Green waste streams.

If not recycled the whole bottle will compost at the landfill site.

Yes -- they are Brits. And they are horrified by the number of plastic bottles their country uses.