morbidly obese rochelle coulson suffers from sleep apnoea - a condition often linked to obesity - which she says leaves her so tired that she falls asleep unexpectedly .
the 21-year-old , who put on 13 stone in four years by eating through boredom ' , has not worked for five years because she would be a ` danger ' in the workplace .
pressure group the taxpayers ' alliance has now warned that the benefit system should not become a ` comfort blanket ' and that