I didn't write those sources but neither did you for your sources.
One of your sources is what the government declares.
I have made a decent case to the contrary.
You claim for enrichment, but sometimes it isn't enough, sometimes people are just so far ahead, for instance Arran Fernandez going into Cambridge at 15.
From one of my sources, "A Nation Deceived"
“Adult surveys of gifted individuals reveal that they do not regret their acceleration. Rather, they regret not having accelerated more.”
From Lubinski, D.,Webb, R.M., Morelock, M. J., Benbow, C. P. (2001),“Top 1 in 10,000:A 10-year follow-up of the profoundly gifted,” in The Journal of Applied Psychology, 86, 718–729.
And tl;dr "The bottom line: Acceleration works. It must be included in the conversation about how to educate a highly capable child. It is time we stopped deceiving ourselves and our children."
Including you, if you're actually attempting to fight against acceleration.
Additionally "Genius Denied: How to Stop Wasting Our Brightest Young Minds"
https://www.amazon.com/Genius-Denied-Wasting-Brightest-Young/dp/0743254619In this book, the Davidsons describe the “quiet crisis” in education: gifted students spending their days in classrooms learning little beyond how to cope with boredom as they “review” material they’ve already mastered years before. This lack of challenge leads to frustration, underachievement, and even failure. Some gifted students become severely depressed. At a time when the UK needs a deep intellectual talent pool, the squandering of future revolutionaries is a tragedy.