I'm in central London and have been very fortunate with childcare.
DD goes to breakfast club at 8am and then afterschool club from 3.15 to 5.30 (hopefully changing to 6pm).
In the holidays/Inset days/Strike days etc the nursery she attended before going to school offers 8-6 care until children turn 11. They also do a breakfast club/afterschool club with drop off and pick up to 5 local primaries.
To be honest, DD loves it. The afterschool club has different activities every day - so far this week they've done gardening, hama beads, making elastic bracelets and fabric hair scrunchies, sports races, trips to the park and general playing around outside. It's like a playdate every afternoon and she also knows children in other classes (she's in YR) and the older ones spoil her rotten. A local restaurant has even offered to have them all for a free pizza and ice-cream at the end of term!
It would be far more boring being with mummy all afternoon and playdates in London flats are not exactly ideal.
We have a 20 minute bus ride in the morning and evening and use that to do reading together. Homework is only once a week so we do that either at the weekend or one evening.
I'm possibly fortunate that DD is inexhaustible, bed-time is therefore pretty late and so doing things in the evening isn't a problem. If she was a child who was so tired she was falling asleep on the bus on the way home then it would be trickier.
The first week of Reception I did organise to pick her up at 3.15, but after 2 days she told me that she'd rather go to after-school club with her friends thank you very much!
I do think that the government should legislate so that all schools must provide 8-6 wrap-around care especially since they are so keen for parents to work, rather than it being a bit of a post-code lottery!