And it’s good she was.
Her performance, appearing in nearly every scene, is the driving force in this very thoughtful movie.
Thompson plays a high court judge, Fiona Maye, who specialises in family law, dealing with often controversial cases.
She is completely wrapped up in her work - so much so she barely notices that her marriage is crumbling, with husband Jack (Stanley Tucci) barely getting noticed.
However, with home life taking a dramatic turn, Fiona Maye has to decide in a case in which a Jehovah’s Witness family are refusing on religious grounds a blood transfusion for their son, who has leukaemia.
Childless herself because work has always come first, the judge is forced to re-evaluate her own life through this case.
Fionn Whitehead (Tommy in the highly successful Dunkirk movie) plays the young man facing certain death without the transfusion and his performance is also excellent.
There’s a great rapport between Thompson and him.
The one niggle I have is that the very excellent Tucci really only has scraps in terms of the script to play with.
Full credit to him that he shows his superb ability with very little to play with.
Any film dealing with religion is likely to be controversial, but the whole Jehovah’s Witness issue about blood transfusion feels more of a catalyst to get the principal players together.
Ian McEwan wrote the screenplay from his original novel to add to his many movies adapted from his books (most recently On Chesil Beach).
As with several of his stories if you’re looking for all the loose ends to be neatly tied them you’ll be disappointed.
Overall it’s a grandstand performance from Thompson and a film that will get you thinking well after the credits roll.
Film details: The Children Act (12A) 105mins - 4 out of 5 stars
Director: Richard Eyre
Starring: Emma Thompson, Stanley Tucci, Fionn Whitehead
Screening courtesy of Horsham Capitol