It’s hard to know where the script, the directing and the acting begin and end given how formidable this very cool, moody, unconsoled rendition of Parade’s End is. But one thing that is certain is that Benedict Cumberbatch’s performance as Tietjens is a thing of wonder. It is not simply a superb piece of acting in a fine TV version of a good book. It is one of the finest things that has ever been done in the medium – a performance that asks for comparison with, say, Günter Lamprecht as Franz Biberkopf in Fassbinder’s miniseries Berlin Alexanderplatz (1980), something that belongs in the rare company of the finest things on film. It is a startling performance not least because it inhabits everything that is awkward and ugly in the character of Tietjens in the book, but it does so with a coherence that dazzles the mind, even as it tugs at the heart. Forget the dapper simplistic smoothie of Sherlock or the tour de force antics of Danny Boyle’s Frankenstein, this is a staggering performance and all the more staggering for the fact that it has the intricacy and style, right down to an uncanny and all-but-archaic mastery of voice and tone and orchestration of colour, that we associate with the Ralph Richardson generation of actors – something that seemed gone with the wind.
This version of Tietjens, who is harrowed beyond every hell of the heart, is a great staring, awkward blob of a man – cavernous, ruinous and pitilessly plain. At the same time there is a great sweetness and an authenticity in the bareness, the absolute starkness, with which Tietjens, stripped of almost everything, is represented by Cumberbatch. It is a magnificent performance and the mightiness of the technical feat it represents in fact pales compared to the power of the feeling it conveys."
— Peter Craven, Screen Education