Working parent here. It sounds like a brilliant idea: free wraparound care for all primary school kids. I'd be interested in how the logistics would play out. My DC don't need paid childcare anymore (thank the Lord!) but easy access to childcare would have saved me so much stress over the years. FWIW, mine were both in nursery from 6m old, and then when they started school I had to source reliable childcare that coincided with my nursing shift times (not easy to find at all, and very expensive). From 2007 to 2023, I was paying either nursery fees, childminder fees, wraparound care fees and holiday club (I've got 2 DC and the youngest has just started in secondary).
If the government plan to sort things so that more childcare spaces are available, to more families, then great: it will help working parents, and it will help parents who aren't working (either to get respite or to enable them to study/train/work). If this means that kids in poor and vulnerable situations get to have breakfast, meals, activities, a safe space and some respite, then that's great too.
The secondary school that my youngest has just started at provides free breakfasts for all students. My daughter sometimes goes in early to have breakfast with her school mates before classes start. She doesn't NEED to (we're very fortunate as a family - I'm healthy and able to work FT, we have food in the cupboards and a warm home), but she enjoys it.
For PP who can't understand how this helps kids...like others have said, there'll be plenty of kids whose families don't have food in the house, or don't have the heating on, or can't afford for their kids to do activities and sports clubs etc. This will surely help those kids.