A once in a century discovery of a cache of long-lost letters has revealed how the English poet WH Auden developed a deep and lasting friendship with a Viennese sex worker and car mechanic after the latter burgled the Funeral Blues author's home and was put on trial. York-born Auden, a prominent member of a generation of 1930s writers that also included Christopher Isherwood, Louis MacNeice and Stephen Spender, described his unconventional arrangement with the man he affectionally called Hugerl.