I also agree with the point Mashabell is making in that ages 4 - 6 in many other countries are still in 'pre-school'/ 'kindergarten'/ 'nursery school' - however these early years environment also include learning alphabets, early reading/ maths skills and often learning foreign languages.
However I believe the English system is historically skewed to getting strapping youths with small fingered lasses into the workforce by age 16 to help progress the industrial revolution. That's changed now - children are to be educated to age 18 by law (www.gov.uk/government/policies/increasing-opportunities-for-young-people-and-helping-them-to-achieve-their-potential). But it remains the case that the English national curriculum starts in Year 1 - and at some schools (not all) homework will start.
Now Mashabell - for my DDs all the way through homework has been given in small doses at both schools (so given on a Thursday/ Friday to be returned on a Monday/ Tuesday) and there is plenty of time and space (if you're organised) to do it in nice small bite size chunks. For DD1 however, homework has been a kind of on again and off for months thing. First term Y5, DD1 had no homework at all - apparently because the school was aware many children (that would be 12 out of the 30 in the cohort) were preparing for the 11+. When we parents raised our concerns at a public curriculum meeting with governors present homework was suddenly reinstated (for which read once in every 3-4 weeks/ about 2 assignments per half-term).
Some schools go in for reading daily (10 - 15 minutes) in Year R (ours did for both DDs + a weeks maths game - usually shape puzzles) - and frankly that's the most formal homework they ever had from the school. DD1 is in Y6 and on average homework does not account for more than 20 - 30 minutes each week and no books are allowed home (even from the school library - apparently too many books lost/ not returned) - and frankly I think that's more damaging. Unfortunately for DD1 she has one of those mothers that helpfully suggests she reads a book whilst waiting for her sister or me to finish something before setting off somewhere and fortunately for me usually DD1 is happy to do so. DD1 also now is in the habit of reading before bed.
I'm presuming - but don't know - that the homework manchestermummy is describing is indeed set over a weekend - where there is plenty of time to fit in 10 - 15 minutes on a task, here and there.
Call me a radical - but I actually adored homework as a child. I liked the challenge, I liked colouring in a map, building a model or finding 10 facts on a subject (in those days we talked to parents and used encyclopedias -maybe even visited the children's section of the local library - but then this was when dinosaurs still roamed the earth) - but with the internet it's so easy to achieve this now at home or a local library. I also adored reading. I liked learning new things/ new words and looked forward to each new assignment.
Today kids have other passions. Video games being the most obvious - and of course there's nothing wrong with that - but some good old fashioned homework and a bit of play in the fresh air, maybe even forcible baking with Mum or grandma won't hurt a child's character much I suspect.
I do get your plea Mashabell to let children be children - but I also think that developing a habit of doing assigned homework, maybe even learning to enjoy the task (bending it to your interests/ chosing topics that interest you/ doing extra art work for it/ etc...) is also good for young minds. DD1 is at a school where there have been whole months with no homework at all and now very late in the day a grammar workbook from a popular publisher (photocopied in its entirety, which one presumes violates copyright law), a spelling workbook (also photocopied), a maths workbook (? from TES) and a creative writing workbook (looks to be borrowed from TES) have been sent home over Easter with a note urging parents to make that final push towards SATs success - very late in the day, not differentiated in any way - so a challenge for children struggling to attain L4, I suspect tricky in places for L4 pupils but a good review, a little to easy for L5 and not of much use if preparing for L6.
DD1 and I have been working our way through this pile of review materials - putting in 30 minutes a day since we broke up for Easter. We are on target to finish everything off by Sunday. DD1 also informs me that many of her friends simply threw the study packs out as they left school. Somewhere along the way a school rarely sending home homework has taught a lot of kids that homework doesn't matter and there's no point. And Mashabell that is a very bad thing going forward to life at senior school www.nfer.ac.uk/publications/HWK01/HWK01.pdf.
HTH