Jim Loach has two obstacles to overcome with his debut film. First, how to do justice to one of the worst British scandals of the 21st century: the shameful deportation of children to abusive care homes in Australia. Second, how will he fare against the inevitable comparisons with his father, Ken Loach.

Oranges and Sunshine (the 7,000 “Child Migrants” forcibly deported to Australia were promised oranges and sunshine) is not a film for the faint-hearted.

It is about children wrenched from their families, lost identities and the shame of injustice. Yet, it is a story that needed to be told. The narrative unfolds from the viewpoint of Margaret Humphreys, the social worker who blew the whistle on the British government programme of Home Children in the late 80s. She tirelessly travelled back and forth between Britain and Australia, suffering harassment and abuse from religious factions threatened by her exposé, to unite the now adult children with their mothers and fathers and bring the whole wretched business to the attention of the public.

Emily Watson gives a masterful performance as Humphreys. Like the film, her performance never veers towards the sentimental, schmaltzy or over-egged. Hugo Weaving (Lord of the Rings, V for Vendetta) and David Wenham (Lord of the Rings, Van Helsing) are also subtle, engrossing and flawless.

Loach’s Derbyshire is bleak, grey and quiet. It is a carefully thought-out period piece with its linos and tea mugs, 80s cars and smoky pubs. Every detail is perfect and it is a nostalgic joy.

So, does Jim Loach overcome the obstacles? Yes, he absolutely triumphs. The group of sceptical, reluctant and chatty friends I watched it with were hushed and absorbed by the end. I’ll be watching out for his next piece of work with a beady eye.