Mine has just done the same thing. Started it to clear the ice off the screen etc. Noticed when it started, the engine was running for about 0.5 seconds before rev. counter or petrol gauge moved. Turned it off and went back inside. Went back out, started fine and parked it on the road. Next time I tried to start it it wouldn't work. Turns over about four times and then stops you cranking it over and you just get a clicking noise as already described. RAC came and couldn't fix it, but I had them fit a crankshaft sensor. Got it towed to local garage. Garage got it to work as follows:
1. Turn ignition on to the second click and leave the car door open so you don't get locked out.
2. Disconnect the battery. (8mm spanner on negative terminal)
3. Wait for 2 or 3 mins.
4. Re-Connect battery.
5. Turn the key off and remove.
6. Get out, shut the door and lock the car.
7. Un-lock the car and try to start it.
This worked first time. It seems to reset the immobiliser or something but cars going great now. Also, the changing of the crankshaft sensor seems to have stopped the "engine running before rev. counter situation".
Hope this works with yours
P.S you might want to make sure the battery's well charged if you've been trying to start it loads of times.