Readers of the brilliant Telegraph Letters page, as Ian Hislop recently lauded it, will be fondly aware of the eclectic combination of learned wisdom, wistful nostalgia and robust good sense that characterise its correspondence. But what of the 95 per cent of the papers huge postbag which never sees the light of day? Some of the best letters inevitably arrive too late for the 24/7 news cycle, or dont quite fit with the rest of the days selection. Others are just a little too whimsical, or indeed too risqu, to publish in a serious newspaper. And more than a few are completely and utterly (and wonderfully) mad, such as the missives youll find within these pages from someone who signs himself merely as M, and believes himself to be the head of MI6. Now, the Telegraph gives the authors of these unpublished letters the stage at last. Baffled, furious, defiant, mischievous, they inveigh and speculate on every subject under the sun, from the rubbish on television these days to the ven