Bacon, ham and sausages are set to be classed alongside cigarettes, arsenic and asbestos as cancer-causing by global health experts. In a report to be published today by the World Health Organisation (WHO), processed meat is expected to be classed as "carcinogenic to humans", the highest of five possible rankings. Fresh red meat is also due to be judged as being bad for people's health. The World Cancer Research Fund (WCRF) has warned for a number of years that there is "strong evidence" that eating a lot of red meat can cause bowel cancer. One possible reason is the organic pigment that gives red meat its colour, known as haem, may damage the lining of the bowel.