Zanussi Washer Dryer WDS.1183W not drying?

For some reason my washer dryer doesn't dry any more. I have tried to run the dry cycle several times but the clothes end up much wetter than they were to start with. Not sure how this happens, but they're just hot and soaking wet at the end of the cycle, so maybe it isn't draining properly, but not sure where the extra water comes from when it is meant to be drying! Any ideas of what could be wrong and how I could fix it would be appreciated