The movie shows Robert Watson-Watt and other British scientists' struggle to invent radar in the years leading to World War II.

Castles in the Sky was commissioned by Janice Hadlow for BBC Two and Kim Shillinglaw, head commissioner for science and natural history.

[1] It was produced by Simon Wheeler for Hero Film and Television with Arabella Page Croft and Kieran Parker as co-producers for Black Camel Pictures.

He said, "The time is right for a contemporary approach to this rich and under-reported vein of British history—it's not like other war stories—if anything it's more akin to a combination of The Social Network and Chariots of Fire than The Dambusters or Reach for the Sky.

Variety took the view that there were "many ways in which 'Castles in the Sky' adheres timidly to biopic convention...from Mark Russell's sugary score to Gill Horn's elegant but unworn costumes.