I had the same problem,which when I removed back I noticed the heater element had blown.I purchased another (approx £32 from TD spares ).After fixing I found that I still had no heat.
After searching web for possible faults I visited E-Spares.co.uk
who recommended buying a set of thermistors at the same time as the element.(thermistors are positioned above element and are easily replaced---they control HOT and COLD drying).
Cost of thermistors set of 2 is approx £4.
Both element and thermistors are easily accessible once you have removed back of machine and are easily removed and replaced.
NOTE you need to loosen right hand side panel to disconnect and replace blue wire double connector.
(You may well have a build up of fluff around motor which should be hoovered -I filled my vac.)
PLEASE disconnect from mains before working on machine.
Note please check age of manufacture as parts are slightly different for machine made prior to 2001.
david, April 2008