Marks & Spencer, Britain's biggest men's clothing retailer, has just completed the largest ever men's size survey. The company hopes to use the results to win back disgruntled customers, and clothing ranges are now being redesigned to take account of men's changing figures. But what effect will the new men's sizing policy have on the bottom line? After all, a similar initiative failed to halt the decline in sales of women's wear. And how does it complement the government-backed Size UK initiative? John Arlidge finds out.