THEY came for him at first light, as the tones of his violin drifted over the ancient battlements of the Tower of London.

Just before 7 o'clock on a chilly autumn morning of October 19, 1915, Fernando Buschmann, 29, kissed the violin and said: ''Goodbye, I shall not want you any more''.

Then he faced the rifles of an eight-man firing squad of the 3rd Battalion Scots Guards, refusing the bandage for his eyes and dying like a ''gentleman.''

Buschmann was perhaps the most famous of the 11 amateur German spies executed in the Tower during the First World War - the first at the Tower since the mid-18th century.

Now a poignant collection of letters written by him just before his death - and by his young widow Valerie shortly afterwards - has surfaced at a London auction house.

The papers, including his death certificate and official copy of the charges against him, retained by the lawyer who had befriended him during his imprisonment, are expected to fetch a modest #400-#600 at a Phillips sale of manuscripts on November 13.

The most heart-rending is from Buschmann's widow to the lawyer, Henry Garrett, imploring him for details of her husband's final moments.

''Was he at least allowed to keep his violin till his last hours? ''she writes.

''Had he much to suffer? Will I find his tomb in London to weep at it? Oh, dear Sir, I am quite broken down - and my only visit is still, to sleep there, where my beloved husband is sleeping. . .'' She writes of his ''young, innocent life'' and the deep loss to ''his unhappy wife and child''.

In truth, Brazilian-born Buschmann's bungling attempts at spying had not amounted to much and he had been hopelessly ill-prepared.

Although interested in aviation, his spymasters gave him the cover of a commercial traveller in cheese, bananas, and safety razors.

Astonishingly, he was lodged at ''a famous hotel in the Strand'' so well-known as a stopping place for spies that it was regularly trawled by the security services.

And his passport was in the handwriting of Flores, head of the German spy school in Rotterdam.

Buschmann gleaned little and his most significant contribution seems to be his observation that searchlights over London began at 8pm and ''if a Zeppelin is not seen or something similar to it at 10.30pm they discontinue the search as they know they dare not come later''.

His letters were intercepted because the German schoolmaster to whom he was told to send his information was known to the British as a spy.

Not surprisingly, Buschmann was soon captured, tried and condemned at Westminster Guildhall on September 20, 1915, spending his final month in the Tower.

His violin was returned to him only the night before he died and he spent his remaining hours playing. His last piece as the guards came for him, was Pagliacci's ''Vesti la giubba'', the story of a broken-hearted clown.

Hours before his death, he wrote to Henry Garrett: ''Once again a thousand, thousand times thanks for all your kindnesses.

''You did me the greatest good, by granting me your so dear company during so many hours of my last day. . . which have so deeply touched me and caused me to find a friend in a foreign country in the most abandoned situation in my life. I die consoled with everybody and pleased to find soon that peace I impatiently await . . .''

Felix Pryor of Phillips, said yesterday: ''The poignancy is all the more profound when you consider Buschmann was really nothing more than an untrained, bungling amateur, controlled by bungling professionals.

''He was expected to send information by writing letters, containing secret writing, to relatives and friends. Incredibly, most addresses were known to the Allies as espionage centres.

''Clearly, the compassion shown during his last month by Garrett was some comfort to his widow.'' Included with the letters and documents is the silver cigarette case which Buschmann's widow presented to Mr Garrett, the lid of which is engraved with the Imperial German and Royal British coats of arms.

The first of the spies to be executed at the Tower was Carl Hans Lody, a German junior naval officer designated to pass himself off as an American tourist and gather information about the loss of British ships.

He arrived in August, 1914 and travelled to Edinburgh where he sent a telegram to an Adolf Burchard in Stockholm, a man monitored by M15. All subsequent communications were read by M15.