It was used to play stirring songs to encourage recruits in the First World War and to cover the noise of prisoners tunnelling to escape from Colditz in the Second. Harry Mead examines the role of the gramophone in modern warfare.

RADAR and the Enigma code-breaking machine: familiar, non-military weapons in the defeat of Nazi Germany. Now it's time to recognise our debt to - wait for it - the gramophone.

Just 12 days after war was declared in 1939, Billy Cotton's dance band recorded a newly-written patriotic song, There'll Always Be An England. Within the following month or so, seven bands and three music hall acts, including Flanagan and Allen, recorded another new ditty, We're Gonna Hang Out Our Washing On The Siegfried Line - German fortifications stretching from Holland to Switzerland.

"There could be no better illustration of how... the British record companies from the very beginning played a significant part in strengthening public confidence in a speedy, successful outcome to the war,'' says Eric Blake.

Recordings of Churchill's wartime broadcasts, issued at the time by HMV, also inspired confidence and resolve, if without the prospect of a swift end. "On radio and on disc people heard a man in whom they instinctively knew they could put their hope and trust,'' he adds.

A former Record Librarian with the British Forces Network radio station, who later headed a department at the London School of Economics and now lives in retirement at Huttons Ambo, near Malton, Blake set out to write a broad social history of the gramophone. But its links with wars and dictators proved so fascinating that he confined himself to this unexplored byway, where he found interest at every turn.

There was a gramophone in Hitler's Berlin bunker, but in the chaos towards the end, finding even a single suitable record to play at the Fuhrer's last-minute wedding to his mistress, Eva Braun, proved difficult. A gramophone in Colditz was played loudly to muffle the sounds of tunnelling for the Great Escape. The machine's mainspring was later turned into a hacksaw, used in the secret construction of a two-seat glider in the castle's empty roof space.

The more pivotal place the gramophone attained in warfare is strikingly illustrated by a picture of a First World War recruiting rally in Trafalgar Square, with two soldiers manning a horn gramophone by the platform. From it would come, says Blake, "the sort of stirring tunes calculated to encourage the potential volunteers to sign on".

The morale-boosting potential of the gramophone in war had first been seized upon in the Spanish-American war of 1898, fought chiefly in Cuba. On disc and cylinder record companies issued trumpet calls and the first of what became known as "descriptives" - theatrical impressions, perhaps of life on a warship, or of a battle.

It was in the Boer War (1899-1902) that patriotic tunes were first played to aid recruitment. In parallel, to boost munitions output, Ben Tillett, a prominent workers' champion, who had visited the front, recorded A Message from the Trenches.

In the First World War descriptives remained popular but, just weeks before the Armistice, HMV made the first battlefield recording - of a British bombardment on Lille. With the proceeds honourably donated to the disabled, the disc was marketed as "an historical record which should be in every home".

Meanwhile, portable gramophones had found their way to the front. Besides bringing soldiers the same comfort and relief through music that the playing of popular records did back home (one officer wrote to Elgar: "Music is all we have to carry on") these were sometimes deployed almost as weapons. Played near enemy trenches, records of messages from deserters persuaded others to surrender.

The Russian leader Lenin broadened the concept, engaging a variety of people to push the communist message on records. Of several made by himself, Blake says these "established a positive bond between the leader and the masses; in this way the gramophone was the earliest medium other than the Press to help in creating the cult of personality..."

Come the Second World War and, alongside the gung-ho or sentimental stuff recorded by the dance bands, records were issued giving advice on first aid and air raid precautions.

Amazingly, "descriptives" not only re-appeared but, in style and content, harked straight back to the First World War. One Parlophone offering was advertised as an Heroic War Episode. Another was entitled Going up the Line by Some of the Boys.

However, as Blake says, "it would not be long before the gramophone became as distinctive a medium as the Press and newsreels for on-the-spot war reporting". An early instance was Charles Gardner's excited description of a dog-fight in the Battle of Britain: "Oh boy, look how they're going... I wouldn't like to be that first Messerschmitt''. Criticised by some as heartless, Gardner's "jubilant" account is defended by Blake who says it "came as a tonic which brought instant encouragement to his listeners".

D-Day, Arnhem, the battle of Monte Cassino - first-hand reports of all these, made on the spot with primitive equipment, were brought to the public via the gramophone. Decca sound engineers helped improve underwater electronic detection and the recording of German night-flight radio messages. For despatch to British PoWs, HMV supplied a disc of The British Grenadiers in which an escape map was sandwiched between two layers of shellac. Its usefulness was enhanced when wax from melted-down records was fashioned into non-magnetic compass cases.

Blake's book is rich in such detail. On the river Main at Frankfurt, the Gestapo conducted speedboat chases to catch young people playing the officially despised and banned jazz on small craft. But it was in Britain on May 19, 1942, that perhaps the gramophone's finest moment, if not finest hour, came.

Set up to record nightingales, BBC equipment incidentally picked up the sound of approaching British bombers, heading for a raid. Blake reports: "Luckily the nightingales were not alarmed as the planes drew near, passed overhead and gradually faded from earshot. The sound of bird song and the heavy drone of the bombers on the resulting recording might fancifully be said to symbolise the contesting voices of peace and war, with the nightingales as the victors.''

But the gramophone itself was soon eclipsed. As Blake says, "the growth of other mass-communication channels left it a much-reduced field in which to operate whenever wars and dictators were the focus of international attention".

Still, thanks to Blake's offbeat book, the place of this little-considered machine at the heart of world-shaping events now has its own hit record.

* Wars, Dictators and the Gramophone 1898-1945 by Eric Charles Blake. Sessions of York, paperback, £10, or £12.80 from the publisher, Huntington Road, York, YO31 9HS.