As a Labour councillor, GP, wife and mother, Keeley Hawes' ambitious Iris Elcock is spinning a lot of plates.

Lucy Kirkwood's treatise on the birth of the NHS in 1948 - viewed through the experience of a Shropshire Doctor - similarly strains to do too much.

Is it a love story, a Brief Encounter-style movie pastiche, or feminist take on social history? It's all of these things and neither in Michael Longhurst's tonally fluctuating nigh three-hour production, featuring a dizzy revolve, lots of props, and the now ubiquitous on-stage camera filming scenes.

Hackney Gazette: Keeley Hawes plays GP Dr Iris Elcock in The Human BodyKeeley Hawes plays GP Dr Iris Elcock in The Human Body (Image: Marc Brenner)

The combination of the excellent Hawes, the Donmar, and the writer of National Theatre's recent fabulous The Witches should have been a winner, but it all feels enervating rather than engrossing.

Despite some crackling dialogue between Hawes' briskly practical, head girlish Iris, and Jack Davenport's apolitical, charming screen idol - home from Hollywood to care for his mother - the knowing references to David Lean's movie, (they meet on a train) and roving camera work serves to distance us from their blossoming romance rather than intensify it.

Davenport is a dab hand at a wry comic line, and does his best to flesh out a man who plays bounders and calls himself a sh*t, but finds himself surprised by love.

A chorus of supporting roles, played by Siobhan Redmond, Pearl Mackie and Tom Goodman-Hill are all excellently delineated, if fleeting.

Goodman-Hill is Iris' war wounded, husband Julian, who is repulsed by her ambition, and as a fellow doctor opposes the new socialist health service that will force him to work for the State rather than himself.

Kirkwood is adept at interweaving big politics with the intimacies of an affair, and the always watchable Hawes is brilliant at showing the personal cost of flaunting expectations around sex and womanhood, and the idealism, inequalities and post war window for change that helped forge the NHS.

In one exchange, Julian predicts it will soon be taken for granted and there will "never be enough" resources. But Iris briskly replies that will not mean the idea has failed, but that "we have failed the idea."

The Human Body runs at The Donmar Warehouse until April 14.