Today is plastic free day. Mrs Chappell did a KS2 assembly about ways that the children could make their packed lunches plastic free, specifically single-use plastic free. Please ask your child about this.
On the Ash webpage there is a very simple biscuit recipe. Making your own biscuits is a cheaper and more environmentally-friendly way to reduce plastic in packed lunches.
We don't need one or two people going plastic free perfectly, we need millions of people going plastic free imperfectly!
Unless someone like you cares a whole awful lot, nothing is going to get better.