Please help car wont start!?

I have an R reg clio which has just had MOT and tax put on but now wont start. It was driving fine, parked it up then when I went to start it the next day, nothing. It turns over but doesnt start and I had a guy out from the RAC who didnt seem to have a clue what the problem was he just said fuel wasnt getting to the spark so checked immobiliser and it seems to be working fine (key opens doors and light goes off as it should) Any ideas would be greatly appreciated!