As part of its 75th anniversary celebrations, the British Film Institute is screening a selection of the remarkable films made by the GPO Film Unit (also, coincidentally, founded in 1933). A precursor to the commercial, the documentary and the public information film, these shorts were initially aimed at explaining and promoting the
General Post Office’s services. More than that, though, the Unit under visionary director John Grierson nurtured talent and encouraged innovation, and created an unparalleled cinematic record of Britain in the Thirties.

Among this first tranche of newly-restored films, released in cinemas and then on DVD under the collective title Love Letters and Live Wires, the best-known is Night Mail. Made in 1936 by Harry Watt and Basil Wright, it depicts a speeding, nocturnal locomotive, delivering urgent correspondence to rich and poor, north and south, young and old alike, the urgent, insistent rhyming narrative by WH Auden echoing the thrum of wheels over sleepers. Night Mail depicts an inter-war Britain poised on the brink of social and technological change and also recalls a time when the postal services were both reliable and romantic. Basil Wright would go on to produce emblematic wartime documentaries including London Can Take It! and Lift Up Your Heads.

If Night Mail is a familiar friend, though, there are also wonderful curios and novelties in this collection. Len Lye’s N or NW subsumes a finger-wagging lesson about using the correct postcode in a story of threatened love that draws on surrealist imagery. The same director marries avant-garde animation to cha-cha danceband music in his beautiful, near-abstract exploration of industrial Britain, Trade Tattoo.

In William Coldstream’s The Fairy of the Phone, a delightfully improbable musical about telecommunications, switchboard operators trillingly enquire: “Is your house on fire?” Love Letters and Live Wires also contains early works by Alberto Cavalcanti, Norman McLaren and Lotte Reiniger.

In publicising this collection, the BFI has likened the telecommunications explosion of the Thirties to the internet revolution of today. It’s unlikely, though, that a contemporary film about a search engine would be as artful, or as fondly recalled by future generations, as the works of the GPO Film Unit.

Until 2 October; www.bfi.org.uk/gpo