When Does "The Children Act" (2014) Take Place?
"The Children Act" is a historical fiction novel written by Ian McEwan that released September 2nd, 2014. So when is "The Children Act" set?
It takes place in the year:
We know this because the real-world eponymous real-world act of British parliament The Children Act 1989 is referred to multiple times. This passed on November 16th, 1989 AD. So it must be after November of 1989 AD.

2012 AD
We know this because the real-world eponymous real-world act of British parliament The Children Act 1989 is referred to multiple times. This passed on November 16th, 1989 AD. So it must be after November of 1989 AD.
Furthermore, "Chapter Two?" refers to the real-world lawyer? Sally Clark (née Lockyer) who was incorrectly imprisoned for the death of her two .
More specifically, much later the narrator tells us, "IT WAS HER impression, though the facts did not bear it out, that in the late summer of 2012, marital or partner breakdown and distress in Great Britain swelled like a freak spring tide"... strongly implying it is summer of 2012 AD in the present.
It was adapted to film in 2017.